By using electric voltage instead of a flowing electric current, researchers from UCLA's Henry Samueli School of Engineering and Applied Science have made major improvements to an ultra-fast, high-capacity class of computer memory known as magnetoresistive random access memory, or MRAM.
The UCLA team's improved memory, which they call MeRAM for magnetoelectric random access memory, has great potential to be used in future memory chips for almost all electronic applications, including smart-phones, tablets, computers and microprocessors, as well as for data storage, like the solid-state disks used in computers and large data centers.
MeRAM's key advantage over existing technologies is that it combines extraordinary low energy with very high density, high-speed reading and writing times, and non-volatility — the ability to retain data when no power is applied, similar to hard disk drives and flash memory sticks, but MeRAM is much faster.
Currently, magnetic memory is based on a technology called spin-transfer torque (STT), which uses the magnetic property of electrons — referred to as spin — in addition to their charge. STT utilizes an electric current to move electrons to write data into the memory.
Yet while STT is superior in many respects to competing memory technologies, its electric current–based write mechanism still requires a certain amount of power, which means that it generates heat when data is written into it. In addition, its memory capacity is limited by how close to each other bits of data can be physically placed, a process which itself is limited by the currents required to write information. The low bit capacity, in turn, translates into a relatively large cost per bit, limiting STT's range of applications.
With MeRAM, the UCLA team has replaced STT's electric current with voltage to write data into the memory. This eliminates the need to move large numbers of electrons through wires and instead uses voltage — the difference in electrical potential — to switch the magnetic bits and write information into the memory. This has resulted in computer memory that generates much less heat, making it 10 to 1,000 times more energy-efficient. And the memory can be more than five-times as dense, with more bits of information stored in the same physical area, which also brings down the cost per bit.
The research team was led by principal investigator Kang L. Wang, UCLA's Raytheon Professor of Electrical Engineering, and included lead author Juan G. Alzate, an electrical engineering graduate student, and Pedram Khalili, a research associate in electrical engineering and project manager for the UCLA–DARPA research programs in non-volatile logic.
"The ability to switch nanoscale magnets using voltages is an exciting and fast-growing area of research in magnetism," Khalili said. "This work presents new insights into questions such as how to control the switching direction using voltage pulses, how to ensure that devices will work without needing external magnetic fields, and how to integrate them into high-density memory arrays.
"Once developed into a product," he added, "MeRAM's advantage over competing technologies will not be limited to its lower power dissipation, but equally importantly, it may allow for extremely dense MRAM. This can open up new application areas where low cost and high capacity are the main constraints."
Said Alzate: "The recent announcement of the first commercial chips for STT-RAM also opens the door for MeRAM, since our devices share a very similar set of materials and fabrication processes, maintaining compatibility with the current logic circuit technology of STT-RAM while alleviating the constrains on power and density."
The research was presented Dec. 12 in a paper called "Voltage-Induced Switching of Nanoscale Magnetic Tunnel Junctions" at the 2012 IEEE International Electron Devices Meeting in San Francisco, the semiconductor industry's "pre-eminent forum for reporting technological breakthroughs in the areas of semiconductor and electronic device technology."
MeRAM uses nanoscale structures called voltage-controlled magnet-insulator junctions, which have several layers stacked on top of each other, including two composed of magnetic materials. However, while one layer's magnetic direction is fixed, the other can be manipulated via an electric field. The devices are specially designed to be sensitive to electric fields. When the electric field is applied, it results in voltage — a difference in electric potential between the two magnetic layers. This voltage accumulates or depletes the electrons at the surface of these layers, writing bits of information into the memory.
"Ultra-low–power spintronic devices such as this one have potential implications beyond the memory industry," Wang said. They can enable new instant-on electronic systems, where memory is integrated with logic and computing, thereby completely eliminating standby power and greatly enhancing their functionality."
The work was supported by the Defense Advanced Research Projects Agency (DARPA) NV Logic Program. Other authors included researchers from the UCLA Department of Electrical Engineering; UC Irvine's Department of Physics and Astronomy; Hitachi Global Storage Technologies (a Western Digital Company); and Singulus Technologies, of Germany.
Wang is also director of the Western Institute of Nanoelectronics (WIN), director of the Center on Functional Engineered Nano Architectonics (FENA) and a member of the California NanoSystems Institute.
The UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs and has an enrollment of more than 5,000 students. The school's distinguished faculty are leading research to address many of the critical challenges of the 21st century, including renewable energy, clean water, health care, wireless sensing and networking, and cybersecurity. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to nine multimillion-dollar interdisciplinary research centers in wireless sensor systems, wireless health, nanoelectronics, nanomedicine, renewable energy, customized computing, the smart grid, and the Internet, all funded by federal and private agencies and individual donors. (www.engineer.ucla.edu | www.twitter.com/uclaengineering)
For more UCLA news, visit the UCLA Newsroom and follow us on Twitter.
Matthew Chin | EurekAlert!
Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
Innovative technique for shaping light could solve bandwidth crunch
20.10.2016 | The Optical Society
Wissenschaftler am MPQ haben mit ultrakurzen Laserpulsen die schnellsten jemals erzeugten elektrischen Ströme in Festkörpern gemessen. Die Elektronen führten in einer Sekunde achtmillionen Milliarden Schwingungen aus, ein absoluter Rekord für die Steuerung von Elektronen in Festkörpern.
Die Leistungsfähigkeit von modernen elektronischen Geräten wie Computern oder Mobilfunkgeräten wird durch die Geschwindigkeit bestimmt, mit der die...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
Auf der weltgrößten Kunststoffmesse K 2016 vom 19. bis 26. Oktober 2016 in Düsseldorf präsentiert sich das Leibniz-Institut für Polymerforschung Dresden e. V....
Mit einem neu entwickelten Rasterkraftmikroskop können Nanodrähte als winzige Sensoren eingesetzt werden – womit sich im Gegensatz zu herkömmlichen Geräten sowohl Grösse als auch Richtung von Kräften messen lassen. Dies berichten Physiker der Universität Basel und der EPF Lausanne im Fachblatt «Nature Nanotechnology».
Nanodrähte sind extrem dünne, langgestreckte Kristalle, die Molekül für Molekül aus verschiedenen Materialien aufgebaut werden können und wegen ihrer...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
20.10.2016 | Veranstaltungen
20.10.2016 | Veranstaltungen
20.10.2016 | Veranstaltungen
20.10.2016 | Geowissenschaften
20.10.2016 | Biowissenschaften Chemie
20.10.2016 | Unternehmensmeldung