Magnetic properties of amorphous Ge-Cr thin films fabricated by thermal evaporation

Ferromagnetic ordering at room temperature is observed in amorphous Ge _100-xCr_x (x in at.%) thin films fabricated by thermal co-evaporation over a wide composition range up to x = 39. High resolution transmission electron microscopy results indicate that the microstructure is mostly amorphous, except for at x = 15 (close to eutectic composition) and 39 where crystalline precipitates of Ge and the intermetallic Ge ₁₉Cr₁₁ compound are respectively formed in an amorphous matrix. The saturation magnetization at room temperature exhibits a maximum value of 2.5 emu/cc at x = 29 and the compositional dependence of saturation magnetization is supported by the microstructural results.