Nav: Home

Magnonic devices can replace electronics without much noise

March 04, 2019

Electronic devices such as transistors are getting smaller and will soon hit the limits of conventional performance based on electrical currents.

Devices based on magnonic currents -- quasi-particles associated with waves of magnetization, or spin waves, in certain magnetic materials -- would transform the industry, though scientists need to better understand how to control them.

Engineers at the University of California, Riverside, have made an important step toward the development of practical magnonic devices by studying, for the first time, the level of noise associated with propagation of magnon current.

Noise, or fluctuations in a current's flow, is an important metric in gauging whether an electronic device is suitable for practical applications. Because noise interferes with a device's performance, a better understanding of how noisy magnons are will help engineers develop better devices.

All existing electronics are based on conductors of electricity such as metals or semiconductors. As electrons move through these materials, they experience scattering, which results in electrical resistance, heating, and energy dissipation. When current passes through a wire or semiconductor, the inevitable heating causes energy loss. Smaller devices and chips with a higher density of transistors accelerate the loss of energy due to heating. Devices using conventional electronic currents are almost at the point where they can't be made any smaller.

A new class of materials possess magnetic properties that originate from spin, a type of innate momentum. Individual "chunks," or units of spin waves, are called magnons. Magnons are not true particles like electrons, but they behave like particles and can be treated as such.

A ripple of energy called a spin wave can move through an electrically insulating material to transmit energy without moving any electrons -- like people doing the wave in a stadium. This means that magnons can propagate without generating much heat and losing much energy.

A new field of electronics called magnonics attempts to create devices for information processing and storage, as well as sensory applications, using currents of magnons instead of electrons. While electron noise has been known for a long time, no one has investigated magnon noise -- until now.

A team led by Alexander Balandin, a distinguished professor of electrical and computer engineering in UC Riverside's Marlan and Rosemary Bourns College of Engineering, created a chip that generated a magnonic current, or spin wave, between transmitting and receiving antennae.

Experiments revealed that magnons are not that noisy at low-power levels. But at high-power levels, the noise became unusual, dominated by broad fluctuations researchers called random telegraph signal noise that would interfere with a device's performance. The noise was noticeably different from that made by electrons and identifies limitations on how to build magnonic devices.

"Magnonic devices should be preferably operating with low-power levels," Balandin said. "One can say that the noise of magnons is discreet at low power but becomes high and discrete at a certain threshold of power. This constitutes the discreet charm of the magnonic devices. Our results also tell us possible strategies for keeping the noise level low."

Would the discovery of unusual noise characteristics inhibit development of magnonic devices?

"No, the goal for information processing is to go to low power," Balandin said.

For now, Balandin's research group is conducting experiments with generic components in order to understand the fundamentals. Their first experimental devices are relatively large. They plan to investigate the physical mechanisms of magnon noise and test a substantially downscaled version of such devices.
The paper, "The discrete noise of magnons," is a feature story in Applied Physics Letters, and will also appear on the cover of an upcoming issue. In addition to Balandin, the authors are Sergey Rumyantsev, Mykhaylo Balinskyy, Fariborz Kargar, and Alexander Khitun.

The work was supported as part of Spins and Heat in Nanoscale Electronic Systems, an Energy Frontier Research Center at UC Riverside funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

University of California - Riverside

Related Electrons Articles:

Deceleration of runaway electrons paves the way for fusion power
Fusion power has the potential to provide clean and safe energy that is free from carbon dioxide emissions.
Shining light on low-energy electrons
The classic method for studying how electrons interact with matter is by analyzing their scattering through thin layers of a known substance.
Ultrafast nanophotonics: Turmoil in sluggish electrons' existence
An international team of physicists has monitored the scattering behavior of electrons in a non-conducting material in real-time.
NASA mission uncovers a dance of electrons in space
NASA's MMS mission studies how electrons spiral and dive around the planet in a complex dance dictated by the magnetic and electric fields, and a new study revealed a bizarre new type of motion exhibited by these electrons.
'Hot' electrons don't mind the gap
Rice University scientists discover that 'hot' electrons can create a photovoltage about a thousand times larger than ordinary temperature differences in nanoscale gaps in gold wires.
Electrons used to control ultrashort laser pulses
We may soon get better insight into the microcosm and the world of electrons.
Supercool electrons
Study of electron movement on helium may impact the future of quantum computing.
Two electrons go on a quantum walk and end up in a qudit
There is a variety of physical systems that can be used to implement a separate quantum bit, but significantly less research has been done into systems of several qubits or qudits.
Radiation that knocks electrons out and down, one after another
Researchers at Japan's Tohoku University are investigating novel ways by which electrons are knocked out of matter.
Controlling electrons in time and space
A new method has been developed to control electrons being emitted from metal tips.

Related Electrons Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".