December 2019

Researchers develop a simple MRAM structure based on unidirectional spin hall magnetoresistance (USMR)

Researchers from the Tokyo Institute of Technology (Tokyo Tech) developed a new MRAM cell structure that relies on unidirectional spin Hall magnetoresistance (USMR). The new cell structure is reportedly very simple with only two layers which could lead to lower-cost MRAM devices.

USMR MRAM cell structure image

The spin Hall effect leads to the accumulation of electrons with a certain spin on the lateral sides of a material. By combining a topological insulator with a ferromagnetic semiconductor, the researchers managed to create a device with giant USMR.

Read the full story Posted: Dec 29,2019

Researchers develop single molecular spin switches

Researchers from Kiel University and European colleagues designed and fabricated single molecular spin switches. The newly developed molecules feature stable spin states and do not lose their functionality upon adsorption on surfaces.

Single molecular spin switches (Kiel University)

The researchers say that the spin states of the new compounds are stable for at least several days. The new molecules have three properties that are coupled with each other in such a feedback loop: their shape (planar or flat), the proximity of two subunits, called coordination (yes or no), and the spin state (high-spin or low-spin). Thus, the molecules are locked either in one or the other state. Upon sublimation and deposition on a silver surface, the switches self-assemble into highly ordered arrays. Each molecule in such an array can be separately addressed with a scanning tunneling microscope and switched between the states by applying a positive or negative voltage.

Read the full story Posted: Dec 25,2019

Researchers show how chiral perovskite films can act as a spin filter

Researchers from the NREL and the University of Utah have demonstrated how electron transport with a particular spin state through a two-dimensional hybrid organic-inorganic perovskite can be manipulated by introducing special organic molecules in the multilayer structure.

One way to control spin-polarized currents is through "chiral-induced" spin selectivity where the transport of electrons depends upon the transporting materials’ chirality—a structural property of a system where its mirror image is not superimposable on itself. The scientists have demonstrated how to integrate a chiral organic sublattice into an inorganic framework, creating a chiral system that can transport electrons with the desired spin control. In such systems, the chiral perovskite films act as a spin filter.

Read the full story Posted: Dec 09,2019

Researchers show that grain boundaries do not effect the spin transport of graphene

Researchers from Spain's ICN2 institute have used numerical simulations to show that spin diffusion length in graphene is independent of grain size. The researchers base their calculations on CVD grown graphene. CVD methods produces high quality materials that are built from several single-crystal sheets separated from one another through grain boundaries.

Graphene seperated by grain boundaries image (ICN2)

The research have shown that the grain boundaries do not have any effect on the spin transport. The researchers considered two different mechanisms for spin relaxation - randomization of spins within the grains due to spin-orbit coupling, and scattering in a grain boundary. The main implication of this research is that single-domain graphene may not be a requirement for spintronics applications.

Read the full story Posted: Dec 05,2019