Exponential magnetic states for memory applications

Exponential magnetic states for memory applications

Spintronics is a thriving branch of nano-electronics which utilizes the spin of the electron and its associated magnetic moment in addition to the electron charge used in traditional electronics.  The main current practical contributions of spintronics are in magnetic sensing and non-volatile magnetic data storage. Expectations are for additional breakthroughs in developing magnetic based processing and novel types of magnetic memory. Spintronics devices commonly consist of magnetic elements manipulated by spin-polarized currents between stable magnetic states. When the spintronic devices are used for storing data, the number of stable states sets an upper bound on memory capacity. While current commercial magnetic memory cells have two stable magnetic states corresponding to two memory states, there are clear advantages to increasing this number as it will potentially allow increasing the memory density and enable the design of novel types of memory.

Now, researchers from the group headed by Prof. Klein from the physics department and the nanotechnology center at Bar-Ilan University have shown that relatively simple structures can support exponential number of states. The studied structures are magnetic thin films patterned in the form of N (=2,3 or 4) crossing ellipses which are shown to support 22N discrete magnetic states. Furthermore, the researchers have demonstrated switching between the states by generating spin currents.

The ability to stabilize and control exponential number of discrete magnetic states in a relatively simple structure constitutes a major contribution to spintronics and it 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. 

Dr. Shubhankar Das (postdoctoral researcher), Ariel Zaig (Master’s student) and Dr. Moty Schultz (laboratory manager) contributed to the research conducted under the supervision of Prof. Klein. The research appears as a featured article on the cover of a June issue of Applied Physics Letters, a leading journal in the field applied physics.

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