Magneto-optical light modulation using the VCMA effect in MgO/Co–Fe/Gd/Gd–Fe layers

Abstract

Voltage-controlled magnetic anisotropy (VCMA) effect of Co–Fe (0.4 nm)/Gd (0.2 nm)/GdxFe100−x multilayers with varying Gd–Fe thickness (5–10 nm) and composition (x = 20–24 at.%) was investigated. The magnetic anisotropy without voltage application drastically changed from in-plane to out of plane with an increase in Gd–Fe thickness or Gd concentration. The VCMA effect was observed in all samples, but the samples with small saturation field (or switching field) showed a clear VCMA effect. The magneto-optical light modulation of the Co–Fe (0.4 nm)/Gd (0.2 nm)/Gd24Fe76 (5 nm) was successfully manipulated via voltage application at ±1 V, in which the amplitude corresponds to 0.15 degrees of the Kerr rotation with a static magnetic field of 50 Oe.