マグノンスピン流媒体としてのガーネット/スピネル型フェライト薄膜の開発

摘要

Magnetic insulators (MIs) have attracted much attention due to its capability of long-range transmission of spin information without Joule heating, where spin current, a flow of spin angular momentum, is transported not by conduction electrons but by magnons. This paper reviews preparation techniques for thin films of representative MIs (YIu, Fe_3O_4) as media of magnonic spin current. Sputtering from ceramic or metal/alloy target is promising technique from the viewpoint of stability, uniformity, oxidation power, throughput, and affinity with the film deposition of heavy metals such as Pt for the electron-spin conversion via the inverse spin Hall effect. Magnon-meaiated thermoelectric conversion, so-called spin Seebeck effect, has been demonstrated using Fe_3O_4 thin film reactively sputtered on a single crystal substrate.