Tag Archives: Tom Fleischman

SkinKit: smart tattoo provides on-skin computing

The SkinKit wearable sensing interface, developed in the Hybrid Body Lab, can be used for health and wellness, personal safety, as assistive technology and for athletic training, among many applications. Hybrid Body Lab/Provided

A November 3, 2022 Cornell University news release on EurekAlert announces a computer you can attach to your skin (Note: Links have been removed),

Researchers at Cornell University have come up with a reliable, skin-tight computing system that’s easy to attach and detach, and can be used for a variety of purposes – from health monitoring to fashion.

On-skin interfaces – sometimes known as “smart tattoos” – have the potential to outperform the sensing capabilities of current wearable technologies but combining comfort and durability has proven challenging.

“We’ve been working on this for years,” said Cindy (Hsin-Liu) Kao, assistant professor of human centered design, and the study’s senior author, “and I think we’ve finally figured out a lot of the technical challenges. We wanted to create a modular approach to smart tattoos, to make them as straightforward as building Legos.”

SkinKit – a plug-and-play system that aims to “lower the floor for entry” to on-skin interfaces for those with little or no technical expertise – is the product of countless hours of development, testing and redevelopment, Kao said. Fabrication is done with temporary tattoo paper, silicone textile stabilizer and water, creating a multi-layer thin film structure they call “skin cloth.” The layered material can be cut into desired shapes and fitted with electronics hardware to perform a range of tasks.

“The wearer can easily attach them together and also detach them,” said Pin-Sung Ku, lead author of the paper and Hybrid Body Lab member. “Let’s say that today you want to use one of the sensors for certain purposes, but tomorrow you want it for something different. You can easily just detach them and reuse some of the modules to make a new device in minutes.”

The paper “SkinKit: Construction Kit for On-Skin Interface Prototyping” was presented at UbiComp ’22, the Association for Computing Machinery’s international joint conference on pervasive and ubiquitous computing.

Here’s a SkinKit video provided by Cornell University’s Hybrid Body Lab,

Tom Fleischman’s November 3, 2022 story for the Cornell Chronicle provides more details about SkinKit (Note: Links have been removed),

SkinKit – a plug-and-play system that aims to “lower the floor for entry” to on-skin interfaces, Kao said, for those with little or no technical expertise – is the product of countless hours of development, testing and redevelopment, she said.

Kao’s lab is also very conscious of cultural differences generally, and she thinks it’s important to bring these devices to diverse populations.

“People from different cultures, backgrounds and ethnicities can have very different perceptions toward these devices,” she said. “We felt it’s actually very important to let more people have a voice in saying what they want these smart tattoos to do.”

To test SkinKit, the researchers first recruited nine participants with both STEM and design backgrounds to build and wear the devices. Their input from the 90-minute workshop helped inform further modifications, which the group performed before conducting a larger, two-day study involving 25 participants with both STEM and design backgrounds.

Devices designed by the 25 study participants addressed: health and wellness, including temperature sensors to detect fever due to COVID-19; personal safety, including a device that would help the wearer maintain social distance during the pandemic; notification, including an arm-worn device that a runner could wear that would vibrate when a vehicle was near; and assistive technology, such as a wrist-worn sensor for the blind that would vibrate when the wearer was about to bump into an object.

Kao said members of her lab, including Ku, took part in the 4-H Career Explorations Conference over the summer, and had approximately 10 middle-schoolers from upstate New York build their own SkinKit devices.

“I think it just shows us a lot of potential for STEM [science, technology, engineering, and mathematics] learning, and especially to be able to engage people who maybe originally wouldn’t have interest in STEM,” Kao said. “But by combining it with body art and fashion, I think there’s a lot of potential for it to engage the next generation and broader populations to explore the future of smart tattoos.”

Here’s a citation for the paper,

SkinKit: Construction Kit for On-Skin Interface Prototyping” by Pin-Sung Ku, Md. Tahmidul Islam Molla, Kunpeng Huang, Priya Kattappurath, Krithik Ranjan, Hsin-Liu Cindy Kao. Proceedings of the ACM [Aossciation for Computing Machinery] on Interactive, Mobile, Wearable and Ubiquitous Technologies Volume 5 Issue 4 Dec 2021 Article No.: 165pp 1–23 DOI: https://doi.org/10.1145/3494989 Published: 30 December 2021

This paper is behind a paywall.

The Hybrid Body Lab can be found here (the pictures are fascinating). Here’s more from their About page,

The Hybrid Body Lab at Cornell University, founded and directed by Prof. Cindy Hsin-Liu Kao, focuses on the invention of culturally-inspired materials, processes, and tools for crafting technology on the body surface. Designing across scales, we explore how body scale interfaces can enhance our relations with everyday products and both natural and man-made environments. We conduct research at the intersection of Human-Computer Interaction, Wearable & Ubiquitous Computing, Digital Fabrication, Interaction Design, and Fashion & Body Art. We synthesize this knowledge to contribute a culturally-sensitive lens to the future of designs that interface the body and the environment. Our current investigations include:

Wearable Technology & On-Skin Interfaces
We develop novel wearable interfaces and fabrication processes, which a focus on skin-conformable or textile-based form factors. By hybridizing miniaturized robotics, machines, and materials with cultural body decoration practices, we investigate how technology can be situated as a culturally meaningful material for crafting our identities.

Designing Skins Across Scales
‘Many different types of machines that were parts of architecture have become parts of our bodies.’ —Bill Mitchell, Me++

We design “skins” that can be adapted across scales, from the architectural to the body scale. We investigate the interactions of a wearer’s body-borne interface with its surrounding ecology. This includes its interaction with other people, objects, to environments. We are also interested in developing skins that can be deployed across scales — from the body to the architectural scale.

Understanding Social Perceptions Towards On-Body Technologies
Wearable devices have evolved towards intrinsic human augmentation, unlocking the human skin as an interface for seamless interaction. However, the non-traditional form factor of these on-skin interfaces may raise concerns for public wear. These perceptions will influence whether a new form of technology will eventually be accepted, or rejected by society.  We investigate the cultural and social concerns that need to be considered when generating on-body technologies for inclusive design.

Emotional robots

This is some very intriguing work,

“I’ve always felt that robots shouldn’t just be modeled after humans [emphasis mine] or be copies of humans,” he [Guy Hoffman, assistant professor at Cornell University)] said. “We have a lot of interesting relationships with other species. Robots could be thought of as one of those ‘other species,’ not trying to copy what we do but interacting with us with their own language, tapping into our own instincts.”

A July 16, 2018 Cornell University news release on EurekAlert offers more insight into the work,

Cornell University researchers have developed a prototype of a robot that can express “emotions” through changes in its outer surface. The robot’s skin covers a grid of texture units whose shapes change based on the robot’s feelings.

Assistant professor of mechanical and aerospace engineering Guy Hoffman, who has given a TEDx talk on “Robots with ‘soul'” said the inspiration for designing a robot that gives off nonverbal cues through its outer skin comes from the animal world, based on the idea that robots shouldn’t be thought of in human terms.

“I’ve always felt that robots shouldn’t just be modeled after humans or be copies of humans,” he said. “We have a lot of interesting relationships with other species. Robots could be thought of as one of those ‘other species,’ not trying to copy what we do but interacting with us with their own language, tapping into our own instincts.”

Their work is detailed in a paper, “Soft Skin Texture Modulation for Social Robots,” presented at the International Conference on Soft Robotics in Livorno, Italy. Doctoral student Yuhan Hu was lead author; the paper was featured in IEEE Spectrum, a publication of the Institute of Electrical and Electronics Engineers.

Hoffman and Hu’s design features an array of two shapes, goosebumps and spikes, which map to different emotional states. The actuation units for both shapes are integrated into texture modules, with fluidic chambers connecting bumps of the same kind.

The team tried two different actuation control systems, with minimizing size and noise level a driving factor in both designs. “One of the challenges,” Hoffman said, “is that a lot of shape-changing technologies are quite loud, due to the pumps involved, and these make them also quite bulky.”

Hoffman does not have a specific application for his robot with texture-changing skin mapped to its emotional state. At this point, just proving that this can be done is a sizable first step. “It’s really just giving us another way to think about how robots could be designed,” he said.

Future challenges include scaling the technology to fit into a self-contained robot – whatever shape that robot takes – and making the technology more responsive to the robot’s immediate emotional changes.

“At the moment, most social robots express [their] internal state only by using facial expressions and gestures,” the paper concludes. “We believe that the integration of a texture-changing skin, combining both haptic [feel] and visual modalities, can thus significantly enhance the expressive spectrum of robots for social interaction.”

A video helps to explain the work,

I don’t consider ‘sleepy’ to be an emotional state but as noted earlier this is intriguing. You can find out more in a July 9, 2018 article by Tom Fleischman for the Cornell Chronicle (Note: tthe news release was fashioned from this article so you will find some redundancy should you read in its entirety),

In 1872, Charles Darwin published his third major work on evolutionary theory, “The Expression of the Emotions in Man and Animals,” which explores the biological aspects of emotional life.

In it, Darwin writes: “Hardly any expressive movement is so general as the involuntary erection of the hairs, feathers and other dermal appendages … it is common throughout three of the great vertebrate classes.” Nearly 150 years later, the field of robotics is starting to draw inspiration from those words.

“The aspect of touch has not been explored much in human-robot interaction, but I often thought that people and animals do have this change in their skin that expresses their internal state,” said Guy Hoffman, assistant professor and Mills Family Faculty Fellow in the Sibley School of Mechanical and Aerospace Engineering (MAE).

Inspired by this idea, Hoffman and students in his Human-Robot Collaboration and Companionship Lab have developed a prototype of a robot that can express “emotions” through changes in its outer surface. …

Part of our relationship with other species is our understanding of the nonverbal cues animals give off – like the raising of fur on a dog’s back or a cat’s neck, or the ruffling of a bird’s feathers. Those are unmistakable signals that the animal is somehow aroused or angered; the fact that they can be both seen and felt strengthens the message.

“Yuhan put it very nicely: She said that humans are part of the family of species, they are not disconnected,” Hoffman said. “Animals communicate this way, and we do have a sensitivity to this kind of behavior.”

You can find the paper presented at the International Conference on Soft Robotics in Livorno, Italy, ‘Soft Skin Texture Modulation for Social Robotics’ by Yuhan Hu, Zhengnan Zhao, Abheek Vimal, and Guy Hoffman, here.

An exoskeleton for a cell-sized robot

A January 3, 2018 news item on phys.org announces work on cell-sized robots,

An electricity-conducting, environment-sensing, shape-changing machine the size of a human cell? Is that even possible?

Cornell physicists Paul McEuen and Itai Cohen not only say yes, but they’ve actually built the “muscle” for one.

With postdoctoral researcher Marc Miskin at the helm, the team has made a robot exoskeleton that can rapidly change its shape upon sensing chemical or thermal changes in its environment. And, they claim, these microscale machines – equipped with electronic, photonic and chemical payloads – could become a powerful platform for robotics at the size scale of biological microorganisms.

“You could put the computational power of the spaceship Voyager onto an object the size of a cell,” Cohen said. “Then, where do you go explore?”

“We are trying to build what you might call an ‘exoskeleton’ for electronics,” said McEuen, the John A. Newman Professor of Physical Science and director of the Kavli Institute at Cornell for Nanoscale Science. “Right now, you can make little computer chips that do a lot of information-processing … but they don’t know how to move or cause something to bend.”

Cornell University has produced a video of the researchers discussing their work (about 3 mins. running time)

For those who prefer text or need it to reinforce their understanding, there’s a January 2, 2018 Cornell University news release (also on EurekAlert but dated Jan. 3, 2018) by Tom Fleischman, which originated the news item,

The machines move using a motor called a bimorph. A bimorph is an assembly of two materials – in this case, graphene and glass – that bends when driven by a stimulus like heat, a chemical reaction or an applied voltage. The shape change happens because, in the case of heat, two materials with different thermal responses expand by different amounts over the same temperature change.

As a consequence, the bimorph bends to relieve some of this strain, allowing one layer to stretch out longer than the other. By adding rigid flat panels that cannot be bent by bimorphs, the researchers localize bending to take place only in specific places, creating folds. With this concept, they are able to make a variety of folding structures ranging from tetrahedra (triangular pyramids) to cubes.

In the case of graphene and glass, the bimorphs also fold in response to chemical stimuli by driving large ions into the glass, causing it to expand. Typically this chemical activity only occurs on the very outer edge of glass when submerged in water or some other ionic fluid. Since their bimorph is only a few nanometers thick, the glass is basically all outer edge and very reactive.

“It’s a neat trick,” Miskin said, “because it’s something you can do only with these nanoscale systems.”

The bimorph is built using atomic layer deposition – chemically “painting” atomically thin layers of silicon dioxide onto aluminum over a cover slip – then wet-transferring a single atomic layer of graphene on top of the stack. The result is the thinnest bimorph ever made. One of their machines was described as being “three times larger than a red blood cell and three times smaller than a large neuron” when folded. Folding scaffolds of this size have been built before, but this group’s version has one clear advantage.

“Our devices are compatible with semiconductor manufacturing,” Cohen said. “That’s what’s making this compatible with our future vision for robotics at this scale.”

And due to graphene’s relative strength, Miskin said, it can handle the types of loads necessary for electronics applications. “If you want to build this electronics exoskeleton,” he said, “you need it to be able to produce enough force to carry the electronics. Ours does that.”

For now, these tiniest of tiny machines have no commercial application in electronics, biological sensing or anything else. But the research pushes the science of nanoscale robots forward, McEuen said.

“Right now, there are no ‘muscles’ for small-scale machines,” he said, “so we’re building the small-scale muscles.”

Here’s a link to and a citation for the paper,

Graphene-based bimorphs for micron-sized, autonomous origami machines by Marc Z. Miskin, Kyle J. Dorsey, Baris Bircan, Yimo Han, David A. Muller, Paul L. McEuen, and Itai Cohen. PNAS [Proceedings of the National Academy of Sciences] 2018 doi: 10.1073/pnas.1712889115 published ahead of print January 2, 2018

This paper is behind a paywall.

(Merry Christmas!) Japanese tree frogs inspire hardware for the highest of tech: a swarmalator

First, the frog,

[Japanese Tree Frog] By 池田正樹 (talk)masaki ikeda – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4593224

I wish they had a recording of the mating calls for Japanese tree frogs since they were the inspiration for mathematicians at Cornell University (New York state, US) according to a November 17, 2017 news item on ScienceDaily,

How does the Japanese tree frog figure into the latest work of noted mathematician Steven Strogatz? As it turns out, quite prominently.

“We had read about these funny frogs that hop around and croak,” said Strogatz, the Jacob Gould Schurman Professor of Applied Mathematics. “They form patterns in space and time. Usually it’s about reproduction. And based on how the other guy or guys are croaking, they don’t want to be around another one that’s croaking at the same time as they are, because they’ll jam each other.”

A November 15, 2017 Cornell University news release (also on EurekAlert but dated November 17, 2017) by Tom Fleischman, which originated the news item, details how the calls led to ‘swarmalators’ (Note: Links have been removed),

Strogatz and Kevin O’Keeffe, Ph.D. ’17, used the curious mating ritual of male Japanese tree frogs as inspiration for their exploration of “swarmalators” – their term for systems in which both synchronization and swarming occur together.

Specifically, they considered oscillators whose phase dynamics and spatial dynamics are coupled. In the instance of the male tree frogs, they attempt to croak in exact anti-phase (one croaks while the other is silent) while moving away from a rival so as to be heard by females.

This opens up “a new class of math problems,” said Strogatz, a Stephen H. Weiss Presidential Fellow. “The question is, what do we expect to see when people start building systems like this or observing them in biology?”

Their paper, “Oscillators That Sync and Swarm,” was published Nov. 13 [2017] in Nature Communications. Strogatz and O’Keeffe – now a postdoctoral researcher with the Senseable City Lab at the Massachusetts Institute of Technology – collaborated with Hyunsuk Hong from Chonbuk National University in Jeonju, South Korea.

Swarming and synchronization both involve large, self-organizing groups of individuals interacting according to simple rules, but rarely have they been studied together, O’Keeffe said.

“No one had connected these two areas, in spite of the fact that there were all these parallels,” he said. “That was the theoretical idea that sort of seduced us, I suppose. And there were also a couple of concrete examples, which we liked – including the tree frogs.”

Studies of swarms focus on how animals move – think of birds flocking or fish schooling – while neglecting the dynamics of their internal states. Studies of synchronization do the opposite: They focus on oscillators’ internal dynamics. Strogatz long has been fascinated by fireflies’ synchrony and other similar phenomena, giving a TED Talk on the topic in 2004, but not on their motion.

“[Swarming and synchronization] are so similar, and yet they were never connected together, and it seems so obvious,” O’Keeffe said. “It’s a whole new landscape of possible behaviors that hadn’t been explored before.”

Using a pair of governing equations that assume swarmalators are free to move about, along with numerical simulations, the group found that a swarmalator system settles into one of five states:

  • Static synchrony – featuring circular symmetry, crystal-like distribution, fully synchronized in phase;
  • Static asynchrony – featuring uniform distribution, meaning that every phase occurs everywhere;
  • Static phase wave – swarmalators settle near others in a phase similar to their own, and phases are frozen at their initial values;
  • Splintered phase wave – nonstationary, disconnected clusters of distinct phases; and
  • Active phase wave – similar to bidirectional states found in biological swarms, where populations split into counter-rotating subgroups; also similar to vortex arrays formed by groups of sperm.

Through the study of simple models, the group found that the coupling of “sync” and “swarm” leads to rich patterns in both time and space, and could lead to further study of systems that exhibit this dual behavior.

“This opens up a lot of questions for many parts of science – there are a lot of things to try that people hadn’t thought of trying,” Strogatz said. “It’s science that opens doors for science. It’s inaugurating science, rather than culminating science.”

Here’s a link to and a citation for the paper,

Oscillators that sync and swarm by Kevin P. O’Keeffe, Hyunsuk Hong, & Steven H. Strogatz. Nature Communications 8, Article number: 1504 (2017) doi:10.1038/s41467-017-01190-3 Published online: 15 November 2017

This paper is open access.

One last thing, these frogs have also inspired WiFi improvements (from the Japanese tree frog Wikipedia entry; Note: Links have been removed),

Journalist Toyohiro Akiyama carried some Japanese tree frogs with him during his trip to the Mir space station in December 1990.[citation needed] Calling behavior of the species was used to create an algorithm for optimizing Wi-Fi networks.[3]

While it’s not clear in the Wikipedia entry, the frogs were part of an experiment. Here’s a link to and a citation for the paper about the experiment, along with an abstract,

The Frog in Space (FRIS) experiment onboard Space Station Mir: final report and follow-on studies by Yamashita, M.; Izumi-Kurotani, A.; Mogami, Y.; Okuno,k M.; Naitoh, T.; Wassersug, R. J. Biol Sci Space. 1997 Dec 11(4):313-20.


The “Frog in Space” (FRIS) experiment marked a major step for Japanese space life science, on the occasion of the first space flight of a Japanese cosmonaut. At the core of FRIS were six Japanese tree frogs, Hyla japonica, flown on Space Station Mir for 8 days in 1990. The behavior of these frogs was observed and recorded under microgravity. The frogs took up a “parachuting” posture when drifting in a free volume on Mir. When perched on surfaces, they typically sat with their heads bent backward. Such a peculiar posture, after long exposure to microgravity, is discussed in light of motion sickness in amphibians. Histological examinations and other studies were made on the specimens upon recovery. Some organs, such as the liver and the vertebra, showed changes as a result of space flight; others were unaffected. Studies that followed FRIS have been conducted to prepare for a second FRIS on the International Space Station. Interspecific diversity in the behavioral reactions of anurans to changes in acceleration is the major focus of these investigations. The ultimate goal of this research is to better understand how organisms have adapted to gravity through their evolution on earth.

The paper is open access.

Textiles that clean pollution from air and water

I once read that you could tell what colour would be in style by looking at the river in Milan (Italy). It may or may not still be true in Milan but it seems that the practice of using the river for dumping the fashion industry’s wastewater is still current in at least some parts of the world according to a Nov. 10, 2016 news item on Nanowerk featuring Juan Hinestroza’s work on textiles that clear pollution,

A stark and troubling reality helped spur Juan Hinestroza to what he hopes is an important discovery and a step toward cleaner manufacturing.

Hinestroza, associate professor of fiber science and director of undergraduate studies in the College of Human Ecology [Cornell University], has been to several manufacturing facilities around the globe, and he says that there are some areas of the planet in which he could identify what color is in fashion in New York or Paris by simply looking at the color of a nearby river.

“I saw it with my own eyes; it’s very sad,” he said.

Some of these overseas facilities are dumping waste products from textile dying and other processes directly into the air and waterways, making no attempt to mitigate their product’s effect on the environment.

“There are companies that make a great effort to make things in a clean and responsible manner,” he said, “but there are others that don’t.”

Hinestroza is hopeful that a technique developed at Cornell in conjunction with former Cornell chemistry professor Will Dichtel will help industry clean up its act. The group has shown the ability to infuse cotton with a beta-cyclodextrin (BCD) polymer, which acts as a filtration device that works in both water and air.

A Nov. 10, 2016 Cornell University news release by Tom Fleischman provides more detail about the research,

Cotton fabric was functionalized by making it a participant in the polymerization process. The addition of the fiber to the reaction resulted in a unique polymer grafted to the cotton surface.

“One of the limitations of some super-absorbents is that you need to be able to put them into a substrate that can be easily manufactured,” Hinestroza said. “Fibers are perfect for that – fibers are everywhere.”

Scanning electron microscopy showed that the cotton fibers appeared unchanged after the polymerization reaction. And when tested for uptake of pollutants in water (bisphenol A) and air (styrene), the polymerized fibers showed orders of magnitude greater uptakes than that of untreated cotton fabric or commercial absorbents.

Hinestroza pointed to several positives that should make this functionalized fabric technology attractive to industry.

“We’re compatible with existing textile machinery – you wouldn’t have to do a lot of retooling,” he said. “It works on both air and water, and we proved that we can remove the compounds and reuse the fiber over and over again.”

Hinestroza said the adsorption potential of this patent-pending technique could extend to other materials, and be used for respirator masks and filtration media, explosive detection and even food packaging that would detect when the product has gone bad.

And, of course, he hopes it can play a role in a cleaner, more environmentally responsible industrial practices.

“There’s a lot of pollution generation in the manufacture of textiles,” he said. “It’s just fair that we should maybe use the same textiles to clean the mess that we make.”

Here’s a link to and a citation for the paper,

Cotton Fabric Functionalized with a β-Cyclodextrin Polymer Captures Organic Pollutants from Contaminated Air and Water by Diego M. Alzate-Sánchez†, Brian J. Smith, Alaaeddin Alsbaiee, Juan P. Hinestroza, and William R. Dichtel. Chem. Mater., Article ASAP DOI: 10.1021/acs.chemmater.6b03624 Publication Date (Web): October 24, 2016

Copyright © 2016 American Chemical Society

This paper is open access.

One comment, I’m not sure how this solution will benefit the rivers unless they’re thinking that textile manufacturers will filter their waste water through this new fabric.

There is another researcher working on creating textiles that remove air pollution, Tony Ryan at the University of Sheffield (UK). My latest piece about his (and Helen Storey’s) work is a July 28, 2014 posting featuring a detergent that deposits onto the fabric nanoparticles that will clear air pollution. At the time, China was showing serious interest in the product.

Creating multiferroic material at room temperature

A Sept. 23, 2016 news item on ScienceDaily describes some research from Cornell University (US),

Multiferroics — materials that exhibit both magnetic and electric order — are of interest for next-generation computing but difficult to create because the conditions conducive to each of those states are usually mutually exclusive. And in most multiferroics found to date, their respective properties emerge only at extremely low temperatures.

Two years ago, researchers in the labs of Darrell Schlom, the Herbert Fisk Johnson Professor of Industrial Chemistry in the Department of Materials Science and Engineering, and Dan Ralph, the F.R. Newman Professor in the College of Arts and Sciences, in collaboration with professor Ramamoorthy Ramesh at UC Berkeley, published a paper announcing a breakthrough in multiferroics involving the only known material in which magnetism can be controlled by applying an electric field at room temperature: the multiferroic bismuth ferrite.

Schlom’s group has partnered with David Muller and Craig Fennie, professors of applied and engineering physics, to take that research a step further: The researchers have combined two non-multiferroic materials, using the best attributes of both to create a new room-temperature multiferroic.

Their paper, “Atomically engineered ferroic layers yield a room-temperature magnetoelectric multiferroic,” was published — along with a companion News & Views piece — Sept. 22 [2016] in Nature. …

A Sept. 22, 2016 Cornell University news release by Tom Fleischman, which originated the news item, details more about the work (Note: A link has been removed),

The group engineered thin films of hexagonal lutetium iron oxide (LuFeO3), a material known to be a robust ferroelectric but not strongly magnetic. The LuFeO3 consists of alternating single monolayers of lutetium oxide and iron oxide, and differs from a strong ferrimagnetic oxide (LuFe2O4), which consists of alternating monolayers of lutetium oxide with double monolayers of iron oxide.

The researchers found, however, that they could combine these two materials at the atomic-scale to create a new compound that was not only multiferroic but had better properties that either of the individual constituents. In particular, they found they need to add just one extra monolayer of iron oxide to every 10 atomic repeats of the LuFeO3 to dramatically change the properties of the system.

That precision engineering was done via molecular-beam epitaxy (MBE), a specialty of the Schlom lab. A technique Schlom likens to “atomic spray painting,” MBE let the researchers design and assemble the two different materials in layers, a single atom at a time.

The combination of the two materials produced a strongly ferrimagnetic layer near room temperature. They then tested the new material at the Lawrence Berkeley National Laboratory (LBNL) Advanced Light Source in collaboration with co-author Ramesh to show that the ferrimagnetic atoms followed the alignment of their ferroelectric neighbors when switched by an electric field.

“It was when our collaborators at LBNL demonstrated electrical control of magnetism in the material that we made that things got super exciting,” Schlom said. “Room-temperature multiferroics are exceedingly rare and only multiferroics that enable electrical control of magnetism are relevant to applications.”

In electronics devices, the advantages of multiferroics include their reversible polarization in response to low-power electric fields – as opposed to heat-generating and power-sapping electrical currents – and their ability to hold their polarized state without the need for continuous power. High-performance memory chips make use of ferroelectric or ferromagnetic materials.

“Our work shows that an entirely different mechanism is active in this new material,” Schlom said, “giving us hope for even better – higher-temperature and stronger – multiferroics for the future.”

Collaborators hailed from the University of Illinois at Urbana-Champaign, the National Institute of Standards and Technology, the University of Michigan and Penn State University.

Here is a link and a citation to the paper and to a companion piece,

Atomically engineered ferroic layers yield a room-temperature magnetoelectric multiferroic by Julia A. Mundy, Charles M. Brooks, Megan E. Holtz, Jarrett A. Moyer, Hena Das, Alejandro F. Rébola, John T. Heron, James D. Clarkson, Steven M. Disseler, Zhiqi Liu, Alan Farhan, Rainer Held, Robert Hovden, Elliot Padgett, Qingyun Mao, Hanjong Paik, Rajiv Misra, Lena F. Kourkoutis, Elke Arenholz, Andreas Scholl, Julie A. Borchers, William D. Ratcliff, Ramamoorthy Ramesh, Craig J. Fennie, Peter Schiffer et al. Nature 537, 523–527 (22 September 2016) doi:10.1038/nature19343 Published online 21 September 2016

Condensed-matter physics: Multitasking materials from atomic templates by Manfred Fiebig. Nature 537, 499–500  (22 September 2016) doi:10.1038/537499a Published online 21 September 2016

Both the paper and its companion piece are behind a paywall.