Solid solutions of MnSb as recording media in optical memory applications

Abstract

We show in this paper that many of the difficulties, encountered in using the ferromagnetic MnSb films as storage media in memory devices employing the technique of laser Curie point writing and magneto-optic readout, can be overcome by forming solid solutions of MnSb with Fe, Co, In, and excess Mn, viz. Mn1-xFexSb, Mn1-xCo xSb, MnSb1-xInx and Mn 1+xSb (0≤x≤0.25 or 0.3). Spins that are in basal plane of MnSb at 300 K are found to reorient to be along the film normal, from ferromagnetic resonance work, beyond a critical composition (xc=0.16, 0.21, 0.16, and 0.14 for the systems containing Co, Fe, In, and excess Mn, respectively) ensuring a large readout efficiency. Moreover, the lowering of Curie temperature for higher compositions can enable us to work with low power lasers which help to achieve sharper writing without diffusion of heat into neighboring domains. In addition, the absence of any crystallographic phase transformation in the temperature range of operation (unlike in MnBi) makes the MnSb alloys potentially more attractive for use as recording media.