Magneto‐optical properties of amorphous terbium–iron alloys

The magneto‐optical properties of rf sputtered amorphous TbxFe1−x alloys (with 0.17≤x≤0.32) were investigated using reflectivity and polar Kerr measurements from a surface overcoated in situ with SiO2. The concentration dependence of the Curie temperature, compensation temperature, and low‐temperature polar Kerr amplitude were all derived and the results compared with a mean‐field theory. The temperature behavior of the coercive force was also determined. While a considerable degree of agreement is obtained with earlier work, it appears that the low‐temperature polar Kerr amplitude can only be determined by the iron sub‐network alone, if the iron moment increases with terbium concentration. The extent to which this view is justified is examined in light of current ideas.The magneto‐optical properties of rf sputtered amorphous TbxFe1−x alloys (with 0.17≤x≤0.32) were investigated using reflectivity and polar Kerr measurements from a surface overcoated in situ with SiO2. The concentration dependence of the Curie temperature, compensation temperature, and low‐temperature polar Kerr amplitude were all derived and the results compared with a mean‐field theory. The temperature behavior of the coercive force was also determined. While a considerable degree of agreement is obtained with earlier work, it appears that the low‐temperature polar Kerr amplitude can only be determined by the iron sub‐network alone, if the iron moment increases with terbium concentration. The extent to which this view is justified is examined in light of current ideas.