Recently discovered phenomenon could provide a way to bypass the limits to Moore’s Law.
|“One of the biggest missing pieces” needed to make skyrmions a practical data-storage medium, Geoffrey Beach says, was a reliable way to create them when and where they were needed. “So this is a significant breakthrough.” Illustration by Moritz Eisebitt|
New research has shown that an exotic kind of magnetic behavior discovered just a few years ago holds great promise as a way of storing data — one that could overcome fundamental limits that might otherwise be signaling the end of “Moore’s Law,” which describes the ongoing improvements in computation and data storage over recent decades.
Rather than reading and writing data one bit at a time by changing the orientation of magnetized particles on a surface, as today’s magnetic disks do, the new system would make use of tiny disturbances in magnetic orientation, which have been dubbed “skyrmions.” These virtual particles, which occur on a thin metallic film sandwiched against a film of different metal, can be manipulated and controlled using electric fields, and can store data for long periods without the need for further energy input.
In 2016, a team led by MIT associate professor of materials science and engineering Geoffrey Beach documented the existence of skyrmions, but the particles’ locations on a surface were entirely random. Now, Beach has collaborated with others to demonstrate experimentally for the first time that they can create these particles at will in specific locations, which is the next key requirement for using them in a data storage system. An efficient system for reading that data will also be needed to create a commercializable system.
The new findings are reported this week in the journal Nature Nanotechnology, in a paper by Beach, MIT postdoc Felix Buettner, and graduate student Ivan Lemesh, and 10 others at MIT and in Germany.
The system focuses on the boundary region between atoms whose magnetic poles are pointing in one direction and those with poles pointing the other way. This boundary region can move back and forth within the magnetic material, Beach says. What he and his team found four years ago was that these boundary regions could be controlled by placing a second sheet of nonmagnetic heavy metal very close to the magnetic layer. The nonmagnetic layer can then influence the magnetic one, with electric fields in the nonmagnetic layer pushing around the magnetic domains in the magnetic layer. Skyrmions are little swirls of magnetic orientation within these layers, Beach adds.
Read more at the MIT News Office.
David Chandler | MIT News Office
October 2, 2017
MIT faculty and alumni have helped to shape Cambridge, Boston, and the surrounding region.
|On Sept. 28 at the Boch Center Wang Theatre in downtown Boston, more than a thousand New England alumni will join President L. Rafael Reif in celebrating the countless ways that the MIT community has contributed to the region’s vitality and unmistakable character — and to envision, together, the positive change this community can have on the entire world.|
The history of MIT is one of self-transformation — of a university “restlessly reinventing itself,” as President L. Rafael Reif has put it. But how MIT has changed is just part of its story. The people whose lives and careers are shaped at MIT go out in turn to improve the world around them. This is the premise of the MIT Campaign for a Better World, and its promise: that MIT’s talent and resources are directed toward humanity’s greatest challenges.
The campaign launched in May 2016 with a celebration on campus, then gathered momentum through Better World events that have brought together alumni and friends of MIT in cities worldwide. This week, the series comes home to Boston. On the eve of a local gathering that considers the Institute’s impact on the world, it’s an opportune moment to review the contributions — many more than can be listed here — that MIT’s faculty and alumni have made just beyond the campus, in Cambridge, Boston, and greater New England.
Perhaps MIT’s clearest influence on its environs is at the intersection of life sciences and technology. East Cambridge’s Kendall Square has emerged as a biotech hub around neighborhood anchors like Biogen, founded by Institute Professor and Nobel laureate Phillip Sharp.
Among the numerous new players are TARIS Biomedical, a drug-delivery spinout of the Cima and Langer Labs developed with support from MIT’s Deshpande Center for Technological Innovation, and Cognito Therapeutics, which applies research from the Tsai and Boyden Labs to address neurodegenerative diseases such as Alzheimer’s.
Read more at the MIT News Office.
September 27, 2017
Unusual fluorescent materials could be used for rapid light-based communications systems.
|In this image, light strikes a molecular lattice deposited on a metal substrate. The molecules can quickly exchange energy with the metal below, a mechanism that leads to a much faster response time for the emission of fluorescent light from the lattice. Courtesy of the researchers|
Two-dimensional materials called molecular aggregates are very effective light emitters that work on a different principle than typical organic light-emitting diodes (OLEDs) or quantum dots. But their potential as components for new kinds of optoelectronic devices has been limited by their relatively slow response time. Now, researchers at MIT, the University of California at Berkeley, and Northeastern University have found a way to overcome that limitation, potentially opening up a variety of applications for these materials.
The findings are described in the journal Proceedings of the National Academy of Sciences, in a paper by MIT associate professor of mechanical engineering Nicholas X. Fang, postdocs Qing Hu and Dafei Jin, and five others.
The key to enhancing the response time of these 2-D molecular aggregates (2DMA), Fang and his team found, is to couple that material with a thin layer of a metal such as silver. The interaction between the 2DMA and the metal that is just a few nanometers away boosts the speed of the material’s light pulses more than tenfold.
Read more at the MIT News Office.
David L. Chandler | MIT News Office
Sept. 18, 2017
Summer Scholar Stephanie Bauman interns in Luqiao Liu lab synthesizing and testing manganese gallium samples for spintronic applications.
Assistant Professor of Electrical Engineering Luqiao Liu is developing new magnetic materials known as antiferromagnets, such as manganese gallium samples, that can be operated at room temperature by reversing their electron spin and can serve as the basis for long lasting, spintronic computer memory. Materials Processing Center – Center for Materials Science and Engineering [MPC-CMSE] Summer Scholar Stephanie Bauman spent her internship making and testing these new materials.
Bauman, a University of South Florida physics major, says, “In our project we're working on the area of spintronics, anti-ferromagnetic devices that switch electron spin controlled by a current. I'm working with a lot of new equipment like the vibrating sample magnetometer and the sputterer to lay down thin films.”
“I’ve been working on a daily basis with Joe Finley, who is a graduate student here, and he’s been a explaining a lot of things to me,” Bauman notes. “It’s a very dense subject matter. And he does help me out a lot when we go to things like the X-ray diffraction room, and he shows me how the graphs can interpret how thick each layer of the thin layers of the devices are. He’s really helpful and easy to work with.”
During a visit to the lab, where she synthesizes these thin films with a special machine called a sputter deposition chamber, Bauman says, “I always go back to the checklist just to make sure I'm doing everything in the right order.” In order to take out a sample from the machine she has to follow a complicated set of steps, making sure its parts are correctly lined up and unhooking the sample holder in the main chamber. Because the chamber is pressurized, she must bring it back to everyday atmospheric pressure before taking it out. “Now that I can see that it disengaged, I go ahead and move it all the way back up,” she says. With the sample holder on a moveable arm, she can rotate it out.
|2017 MPC-CMSE Summer Scholar Stephanie Bauman holds a sample of manganese gallium, a new material known as an antiferromagnet, that can serve as the basis for long lasting, spintronic computer memory devices operated by reversing electron spin at room temperature. She interned this summer in the lab of Assistant Professor of Electrical Engineering Luqiao Liu. Photo, Denis Paiste, Materials Processing Center.|
The sample moves across a gear arm out of the main chamber into transfer chamber known as a load lock. “A very, very important part of this is to make sure you close the transfer valve again, otherwise you mess up the pressure in the main chamber,” she says. After double-checking the transfer valve is closed, she brings the load lock back to sea level pressure of 760 Torr. Then she takes out the sample holder.
“As you can see the sample is really tiny. It's half a centimeter by a half a centimeter, which is what we're working with right now,” Bauman says. As she loosens the screws on the arms holding the sample in place, she notes that she has to be careful not to scratch the sample with the arms. Once safely removed, she places the sample in a special holder labeled based on when each sample was made, which sample of the day it is and its thickness. That way, she notes, “we can refer back to that in our data so that we know what thickness levels that we’re testing.”
“Sometimes you end up playing tiddlywinks. I know that some younger people don't really know what that game is, but it's what it looks like when you push down on the arm, and the sample goes flying,” Bauman cautions.
Bauman then demonstrates how a new sample is loaded into the sputterer device. “Carefully tighten the screw, making sure not to torque it too much, then you move the other arm into place,” she says. Once both arms are tightened on the sample holder, she can put the sample into the load lock. “Very simple just make sure it's lined up correctly. It's also important to make sure the O-ring is clean, and so is the lid before you put it back on. That way there's a very good seal. So that's really it for the loading, and then you just turn the vacuum pumps back on and wait until it reaches the appropriate pressure and then load it into the main chamber.”
“I'm actually a non-traditional student, which means I'm a little bit older,” Bauman explains. “I have been in the military for 20 years, and I also had a civilian career for a long time in aviation contracts. I decided to go back to school for physics, and it's really been rewarding, especially this internship.”
Bauman’s internship is supported in part by NSF’s Materials Research Science and Engineering Centers program [grant DMR-14-19807]. Participants in the Research Experience for Undergraduates, co-sponsored by the Materials Processing Center and the Center for Materials Science and Engineering, presented their results at a poster session during the last week of the program. The program ran from June 15, 2017, to August 5, 2017, on the MIT campus in Cambridge, Mass.
– Denis Paiste, Materials Processing Center
Sept. 25, 2017
|2017 MPC-CMSE Summer Scholar Stephanie Bauman presents her poster on her internship in the lab of Assistant Professor of Electrical Engineering Luqiao Liu making and testing new materials known as antiferromagnets, such as manganese gallium, that can serve as the basis for long lasting, spintronic computer memory devices operated by reversing their electron spin at room temperature. Photo, Denis Paiste, Materials Processing Center.|
New venture launched by MIT will support “tough-tech” companies at work on transformative ideas that take time to commercialize.
|Courtesy of The Engine|
The Engine, founded last year by MIT, has announced investments in its first group of seven startups that are developing innovations poised for transformative impact on aerospace, renewable energy, synthetic biology, medicine, and other sectors.
The founding startups were featured Sept. 19 at an event to celebrate the official opening of The Engine’s headquarters at 501 Massachusetts Ave. in Cambridge, Massachusetts, now renovated to include three floors of conference rooms, maker spaces, labs with cutting-edge equipment, computer stations, and other amenities.
“As we look at the first seven companies we have invested in, it is wonderful to see the breadth of tough-tech areas founders have leaned into,” says Katie Rae, president and CEO of The Engine. “We have been so gratified by the quality and passion of the founders that have come to us. These entrepreneurs are on a mission, and with our help they are going to change the world for the better.”
The seven startups are:
- Analytical Space, developing systems that provide no-delay, high-speed data from space, to address global challenges such as precision agriculture, climate monitoring, and city planning;
- Baseload Renewables, developing ultra low-cost energy storage to replace fossil baseload generation with renewable energy to successfully reduce carbon on a global level;
- C2Sense, building a digital olfactory sensor for industrial use cases such as food, agriculture, and worker safety, and transforming smell into real-time data that can be accessed remotely;
- iSee, delivering the next generation of humanistic artificial intelligence technology for human and robotic collaborations, including autonomous vehicles;
- Kytopen, accelerating the development of genetically engineered cells by developing technology that modifies microorganisms 10,000 times faster than current state-of-the-art methods;
- Suono Bio, enabling ultrasonic targeted delivery of therapeutics and macromolecules across tissues without the need for reformulation or encapsulation; and
- Via Separations, developing a materials technology for industrial separation processes that uses 10 times less energy than traditional methods.
Read more at the MIT News Office.
Rob Matheson | MIT News Office
Sept. 19, 2017
Harnessing these imperfections could have implications for computer memory and energy conversion.
|In this diagram, the atomic lattice of a crystal of barium oxide is depicted, with atoms of oxygen and barium represented by red and gray spheres. A neutral oxygen vacancy, a place where an oxygen atom should appear in the lattice but is instead replaced by two electrons, is represented by the yellow shape, which depicts the charge density of those electrons. At left, the crystal is seen with no electric field applied, and at right, with an applied field of 21.8 megavolts per centimeter. The distortions of the lattice reveal the effects of that applied electric field. Image, Felice Frankel|
Sometimes things that are technically defects, such as imperfections in a material’s crystal lattice, can actually produce changes in properties that open up new kinds of useful applications. New research from a team at MIT shows that such imperfections in a family of materials known as insulating metal oxides may be key to their performance for a variety of high-tech applications, such as nonvolatile memory chips and energy conversion technologies.
The findings are reported this week in the journal Physical Review Letters, in a paper by MIT Associate Professor Bilge Yildiz, Professor and Associate Provost Krystyn Van Vliet, and former postdoc Mostafa Youssef.
These metal oxide materials have been investigated by many researchers, Yildiz says, and “their properties are highly governed by the number and the kind of defects that are present.” When subjected to strong driving forces, such as strong electric fields, “the behavior of such defects had not been well-understood,” she says.
Researchers do have a well-established theoretical understanding of how perfectly structured versions of these insulating metal oxides function under a variety of conditions, such as in strong electric fields, but there was no such theory to describe the materials when they contain common types of defects, according to Yildiz. Understanding these effects quantitatively is important in order to develop this promising family of materials for potential applications including new types of low-energy computer memory and processing devices, electrically based refrigeration, and electro-catalytic energy-conversion devices such as fuel cells.
The team demonstrated a theoretical framework and showed how the stability and structure of a point defect is altered under strong electric fields.
Read more at the MIT News Office.
David L. Chandler | MIT News Office
Sept. 21, 2017
Summer Scholar Grace Noel characterizes new crystal semiconductors with solar cell potential.
2017 Materials Processing Center – Center for Materials Science and Engineering [MPC-CMSE] Summer Scholar Grace Noel explored the process of making and characterizing perovskite crystal materials for possible solar cell use in the lab of William A. Tisdale, ARCO Career Development Professor of chemical engineering. Noel synthesizes these lead bromide perovskite materials with different cations, including methyl ammonium, cesium and formamidinium.
“By changing the cation, you can change the properties of the perovskite,” Noel explains. “The word perovskite refers to a class of semiconductors that have a specific crystal structure, and they're an interesting area of research with applications in photovoltaics.”
MIT chemical engineering graduate student Nabeel Dahod, who studies thermal transport in nanostructured materials for his thesis project, is supervising Noel’s work in the Tisdale Lab. “Perovskites are a particularly new and exciting material with at this point undiscovered thermal transport properties, and this is where Grace's project this summer comes in,” Dahod says.
During a visit to the lab, Dahod and Noel demonstrate how these crystals are dried with a vacuum after wet synthesis. Noel explains that she caps her wet solution with tinfoil, perforated with a small hole in it, to slow the diffusion process. Dahod cautions Noel to set up a trap along with the vacuum so solvent vapors don’t harm the pump. Dahod prompts Noel to make sure the vacuum tube is firmly attached in order to be able pull vacuum through into the funnel.
Noel tests the vacuum process to make sure it is pulling out solvent using a pipette, which extracts a small volume. Noting that not all of the solid crystals made it into the filter, Dahod suggests scraping out the rest. Noel asks whether she should be worried about breaking any of the crystals. “No it's okay. They're pretty robust,” Dahod reassures. “Make sure to get as many of the orange ones as you can.”
At a separate workbench, Noel displays formamidinium single crystals and methylammonium single crystals, which have crystallized for about four days. Noel observes that the methylammonium single crystals are slightly larger and that there is a color difference between the two. “The formamidinium are more red in color,” says Noel, who is a rising senior at Penn State University, where she majors in chemical engineering.
“My project is synthesizing these different perovskites in the two different forms, which are single crystals and microplates,” Noel explains. “Basically the single crystals are crystals that are millimeters in size, whereas the microplates are a lot smaller, so they're more like microns in size. But they should exhibit similar properties to the single crystals. This is advantageous because the single crystals have properties that aren't disturbed by things like defects in the material or grain boundaries. So we have the three different types of microplates with the different cations, and we want to see how the thermal properties of them change based on their composition.”
In CMSE’s Shared Experimental Facilities, Noel analyzes scanning electron microscope [SEM] images of the microplates. Speaking about images on a computer monitor, she notes, “These ones are formamidinium lead bromide perovskites, and they form these little plates that are about 1 to 3 microns. So I'm looking at the microplates to see the different sizes that they are, and looking to see if there are any defects or impurities.”
Noel’s internship is supported in part by NSF’s Materials Research Science and Engineering Centers program [grant DMR-14-19807]. Participants in the Research Experience for Undergraduates, co-sponsored by the Materials Processing Center and the Center for Materials Science and Engineering, presented their results at a poster session during the last week of the program. The program ran from June 15, 2017, to August 5, 2017, on the MIT campus in Cambridge, Mass.
– Denis Paiste, Materials Processing Center
September 25, 2017
MPC-CMSE Summer Scholar Amy Duggal tests how cells respond to a new biopolymer.
MIT Professor Paula T. Hammond’s lab is developing nanomaterials for a wide range of applications ranging from treatment of diseases to regenerative medicine. Hammond is head of the Department of Chemical Engineering and David H. Koch (1962) Professor in Engineering. Materials Processing Center – Center for Materials Science and Engineering [MPC-CMSE] Summer Scholar Amrita [Amy] Duggal assessed the utility of a synthetic proteoglycan developed in the Hammond Lab for biomaterial applications.
Duggal, a biochemistry major from California State University, Channel Islands, says, “My research is based on looking at cellular response as well as cell behavior in presence of the biopolymer.”
MIT Chemistry PhD student Wade Wang supervised Duggal’s work in the lab. “Amy's project is really foundational in looking at the interaction of this new polymer that we've developed in the lab. So we want to characterize exactly how this polymer interacts with cells so we can develop new biomaterials based on this polymer,” Wang explains. Wang previously synthesized graft copolymers of poly(γ-propargyl-L-glutamate) [PPLG], a synthetic polypeptide, and hyaluronic acid [HA], an ubiquitous polysaccharide in the body. Cellular interactions with HA are dependent on it size, so by changing the structure of the graft copolymer containing HA the cellular response can be controlled.
Duggal utilized the scratch test, a cell migration assay commonly used in cancer and wound healing studies, to carry out her project. “Cell migration is an important phenomenon when you're trying to study development, maintenance, as well as metastasis and invasion, in cancer cell lines,” Duggal explains.
“Once these cells are scratched…they are treated with the biopolymer treatment,” Duggal notes. The rate and extent of migration, which contribute to “healing” of the scratch, can be promoted or inhibited by PPLG-HA biopolymer treatment. This response is affected by the architecture and molecular weight the biopolymers, which Duggal is interested in optimizing for wound healing applications.
|MPC-CMSE Summer Scholar Amrita [Amy] Duggal uses a microscope to visualize cell migration in the Hammond Lab. Duggal’s summer internship project studied the effect of a synthetic biopolymer developed in the Hammond Lab on cells that are intentionally damaged to mimic wounds and cancer in people. Photo, Denis Paiste, Materials Processing Center.|
“Once the biopolymeric treatment is added to the cell culture, we can visualize whether the biopolymer treatment inhibits or promotes wound healing in these cells,” Duggal says.
During a visit to the lab, Duggal shows images of the cells she recently scratched and treated with biopolymer to study cell migration. “We use the microscope to visualize and understand cell migration,” Duggal notes. The extent of healing and persistence of damage are apparent from the images. After the damaged cells are treated with the biopolymer and incubated for 8 to 12 hours, visual confirmation is apparent that the gap in those cells has closed significantly. “There seems to be cell migration and wound healing to a certain extent,” she says.
In addition to imaging, Duggal further assessed cellular response to the biopolymer with chemical assays for cellular proliferation. This is important because wound healing is a combination of many cellular behaviors, including migration and proliferation. In particular, Duggal uses BRDU [BromodeoxyUridine], a synthetic nucleoside, as a marker to quantify cell growth.
Duggal’s internship is supported in part by NSF’s Materials Research Science and Engineering Centers program [grant DMR-14-19807]. Participants in the Research Experience for Undergraduates, co-sponsored by the Materials Processing Center and the Center for Materials Science and Engineering, presented their results at a poster session during the last week of the program. The program ran from June 15, 2017, to August 5, 2017, on the MIT campus in Cambridge, Mass.
– Denis Paiste, Materials Processing Center
September 25, 2017
|MPC-CMSE Summer Scholar Amrita [Amy] Duggal presents her research on the effect of a synthetic biopolymer developed in the Hammond Lab on cells that are intentionally damaged to mimic wounds and cancer in people during the annual MPC-CMSE Summer Scholars Poster Session on Aug. 3, 2017. Photo, Denis Paiste, Materials Processing Center.|
Summer Scholar Saleem Iqbal works in the Berggren lab on fabricating and characterizing a temperature-sensitive, three-terminal device based on superconducting nanowires.
|MPC-CMSE Summer Scholar Saleem Iqbal checks the level in a dewar, a special canister of liquid helium, with MIT Postdoctoral Associate Reza Baghdadi. Iqbal tested a sample of a new superconducting memory cell at ultracold temperatures of, about 4.2 kelvins, with liquid helium. Photo, Denis Paiste, Materials Processing Center.|
A heater-Tron, or hTron for short, is a three-terminal device based on superconducting nanowires with ultra-fast switching capabilities. MPC-CMSE Summer Scholar Saleem Iqbal is explored these devices in Professor of Electrical Engineering and Computer Science Karl Berggren’s lab.
To make these devices that operate at extremely low temperatures, Iqbal, a student at the University of New Mexico, uses two processes called electron beam lithography and photolithography. E-beam lithography is used to pattern smaller nanostructures in the hTron, while photolithography is used for patterning larger, micron-scale structures. Both of these processes involve commonly used fabrication techniques such as spin-coating resist, cold development, reactive-ion etching, and liftoff, Iqbal explains.
Iqbal newly learned the technique of reactive-ion etching this summer. “One of the challenges in fabricating these devices is that we need to know the proper etching time to use, so that we don't unexpectedly have an open circuit in the device,” Iqbal says. MIT Postdoctoral Associate Reza Baghdadi, who is supervising Iqbal’s internship in the lab, suggests that a systematic study can be conducted to measure the depth and width of trenches produced using different etching times. These measurements can be performed using atomic force microscopy.
In order to study their function, the devices are wire-bonded to a printed circuit board and lowered into a dewar, a special canister of liquid helium. The helium cools the hTron down to a temperature of 4.2 kelvins, below the temperature at which it switches from normally conducting to superconducting. Then, Iqbal carries out direct current [DC] and radio frequency [RF] measurements to characterize the electrical response and switching characteristics of the devices.
During a visit to the lab, Iqbal explains that these characterization measurements need to be performed in the liquid helium at 4.2 K [-268.95 Celsius]. “So what I'm doing right now is I'm lowering this probe into the dewar of liquid helium. There's a superconducting resistor on the end that lets me know when I've reached the end of the liquid helium on the way back up, so we know the amount that's left in the tank. That way we know we have enough so that we can perform these characterization measurements,” he says.
In addition to fabricating the devices, Iqbal’s project also involves modeling the heat transport in the hTron using a numerical technique called the finite element method. “This should ideally give us an idea of the time it takes for the hTron to switch regimes from superconducting to normally conducting,” Iqbal says.
“If we are able to successfully fabricate these devices, the hTron has potential applications as a logic element in superconducting circuits or as a component of superconducting memory cells,” Iqbal, a rising junior physics major, says. “Both of these implementations hold promise for more energy-efficient data storage and processing, as their superconducting nature implies a lesser amount of power dissipation from resistive heating.”
Iqbal’s internship is supported in part by NSF’s Materials Research Science and Engineering Centers program [grant DMR-14-19807]. Participants in the Research Experience for Undergraduates, co-sponsored by the Materials Processing Center and the Center for Materials Science and Engineering, presented their results at a poster session during the last week of the program. The program ran from June 15, 2017, to August 5, 2017, on the MIT campus in Cambridge, Mass.
|MPC-CMSE Summer Scholar Saleem Iqbal presents a poster summarizing his internship under Professor Karl Berggren. Working with MIT Postdoctoral Associate Reza Baghdadi, Iqbal fabricated a device called a heater-Tron, or hTron, which is a transistor-like device that operates at extremely cold temperatures with potential use in a superconducting memory cell. Photo, Denis Paiste, Materials Processing Center.|