Control of Magnetization Dynamics in Ordered Alloy Systems

抄録

  L1₀-type alloys and L2₁-type Heusler alloys are key materials for future spintronic and magnetic storage devices. L1₀-FePt with high uniaxial magnetic anisotropy is a promising material for ultrahigh density recording because of its high thermal stability of magnetization at a nanometer scale. Co-based Heusler alloys showing high spin polarization of conduction electrons enable us to enhance the magnetoresistance effect. In addition, utilizing the magnetization dynamics in these ordered alloys provides us with new paths in the development of spintronic and magnetic storage devices. In this review, we introduce the control of magnetization switching field for L1₀-FePt exchange-coupled with Ni₈₁Fe₁₉ by utilizing the spin waves in the bilayers, which will be useful for information writing. A nanometer-scaled rf oscillator is also introduced, in which the magnetization dynamics is excited by spin angular momentum transfer. We can improve both the rf output power and the oscillation quality simultaneously by using Co₂(Fe_0.4Mn_0.6)Si Heusler alloy.