Israeli Researchers Find a Way to Stabilize and Control Discrete Magnetic States

July 23, 2020 by Luke James

The research team says that their achievement could be used towards applications such as data storage, magnetic sensing, and neuromorphic computing.

A group of researchers from Bar-Ilan University in Israel claim to have found a way to stabilize and control an “exponential number of discrete magnetic states,” which they hope will pave the way for multi-level magnetic memory which will in turn potentially lead to applications in data storage, magnetic sensing, and neuromorphic computing. 

In the journal Applied Physics Letters, the researchers describe their method which enabled them to fabricate structures consisting of two, three, and four crossing ellipses, which exhibit shape-induced bi-axial, tri-axial, and quadro-axial magnetic anisotropy. The very large number of accessible remanent magnetic states observed in the simple magnetic structures could lead to new spintronics applications including memory devices, the paper says. 


Exciting New Applications

The study focused on magnetic thin films that were aligned in the form of N crossing ellipses, possessing two to the power of 2N magnetization states. During the study, the research team found that they could switch between different magnetic states by generating different spin currents. Through trial and error, they found out how to stabilize and control an exponential number of discrete magnetic states in a relatively simple structure. This, according to the researchers, is a major step forward in the spintronics field. 

"This finding may pave the way to multi-level magnetic memory with extremely large number of states per cell (e.g., 256 states when N=4), be used for neuromorphic computing, and more," said lead researcher Prof. Lior Klein.


Magnetic thin film structures.

Researchers have shown that relatively simple magnetic thin film structures of N crossing ellipses can support two to the power of 2N magnetic states and demonstrated switching between the states with spin currents. Image credit: Lior Klein, Bar-Ilan University.

Increasing Memory Density

The emerging field of spintronics concentrates on the intrinsic spin of the electron and its associated magnetic moment, in addition to its electronic charge, in solid-state devices. It is considered to be one of the most important emerging areas of research due to its potential to provide high speed, low power, and high-density logic and memory electronic devices. 

Spintronics devices typically consist of magnetic elements that are manipulated by spin-polarized currents between stable magnetic states. When they are used for data storage, the number of stable data states sets a limit on memory capacity. If researchers are able to increase the number of magnetic states in a magnetic memory cell—currently, there are two magnetic states corresponding to two memory states—it will potentially increase memory density and lead to novel types of memory solutions.