New ferrimagnetic film could help speed up spintronic devices

Ferrimagnetic insulators are promising materials for spintronics. While metallic ferromagnetic materials are conventionally used in spintronic devices, ferrimagnetic materials have the potential to switch faster and more efficiently, which would help advance the next generation of logic or memory devices.

Bauer et al. grew polycrystalline films of a ferrimagnetic insulator, europium iron garnet (EuIG), films that exhibit many of the same properties as single-crystal EuIG films, including perpendicular magnetic anisotropy (PMA). The magnetization of films with PMA can be efficiently switched by spin-orbit torques from current flowing in an adjacent layer, so they can be used to investigate ŧhe spin-mixing conductance and other film characteristics important to spintronic applications.

The authors found that the PMA in the polycrystalline films can be induced by the thermal expansion mismatch between the film and the substrate.

In addition, Bauer et al. grew garnet films on quartz, silica, silicon and yttria-stabilized zirconia substrates using pulsed laser deposition, with thicknesses between 25 and 49 nanometers. Lead author Jackson Bauer said that their work may help integrate garnet films into commercial microelectronics processing, since garnet films grown on garnet substrates are expensive and unsuitable for integration on silicon.

Source: “Perpendicular magnetic anisotropy and spin mixing conductance in polycrystalline europium iron garnet thin films,” by J. J. Bauer, E. R. Rosenberg, and C. A. Ross, Applied Physics Letters (2019). The article can be accessed at https://doi.org/10.1063/1.5074166 .