Researchers unveil a highly efficient means to reverse magnetization
with spin currents

Date:
April 26, 2022
Source:
Tohoku University
Summary:
Researchers have established a low-cost method of magnetization
reversal on perpendicularly magnetized ferromagnets. Not needing
an external magnetic field, the method brings reverse magnetization
closer to commercial viability.



FULL STORY ==========================================================================
An international research team has achieved an important milestone in the
quest for high density, low-power consuming nonvolatile magnetic memory.


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"We established a new method to enable magnetization reversal on perpendicularly magnetized ferromagnets -- without the need for an
external magnetic field," said Makoto Kohda, co-author of the study and professor at Tohoku University's Graduate School of Engineering.

Spintronic devices optimize the intrinsic spin of electrons and their associated magnetic movement. With society needing better performing electronics with less power consumption, spintronics will play a large
part in next-generation nanoelectronic devices.

A spin current converted from a charge current creates a spin-orbit torque (SOT) on ferromagnets, enabling electrical control of the magnetization.

Currently, this is done unidirectionaly and external magnetic fields
must be used to switch perpendicular magnetized ferromagnets. So-called
field free switching, along with diminished current density for reduced
energy consumption, is essential for commercial viability.

Kohda and his team comprised Professor Emeritus Junsaku Nitta from Tohoku University's Graduate School of Engineering and colleagues from the Korea Advanced Institute of Science and Technology (KAIST), such as researcher Jeonchun Ryu, professor Byong-Guk Park and professor Kyung-Jin Lee.

They harnessed spin generated in all directions to create field free
switching using polycrystalline CoFeB/Ti/CoFeB -- crucial because
this material is already employed in the mass production of spintronic
devices. Furthermore, the new method brought about a 30% lower current
density than existing spin current based magnetization reversal.

"International collaboration is the key for demonstrating next-generation technology in nonvolatile memory. The next step for us will be to apply
this principle to spintronic devices' mass production to help usher in
the power- saving technology required for IoT and AI," added Kohda.


========================================================================== Story Source: Materials provided by Tohoku_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jeongchun Ryu, Ryan Thompson, Jae Yeol Park, Seok-Jong Kim,
Gaeun Choi,
Jaimin Kang, Han Beom Jeong, Makoto Kohda, Jong Min Yuk, Junsaku
Nitta, Kyung-Jin Lee, Byong-Guk Park. Efficient spin-orbit torque
in magnetic trilayers using all three polarizations of a spin
current. Nature Electronics, 2022; DOI: 10.1038/s41928-022-00735-9 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220426101750.htm

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