Magnetic Properties of Amorphous Rare Earth‐Transition Metal Alloys Containing a Single Magnetic Species

Abstract

The analysis of magnetic data on most amorphous rare earth‐transition metal binary alloys studied to date is complicated by the fact that both constituents are magnetic. To avoid this problem we have studied amorphous films of Gd 1− x Cu x , with x =0.76, 0.82, 0.86 and Lu1−x, Fex, La 1− x Fe x and Y 1− x Fe x with 0.67< x <0.85 . The GdCu alloys have T c =53 K , 40K, 35K implying a Gd‐Gd exhange about 1/2 that of Gd metal. Significant differences between the magnetic properties of LaFe , LuFe , and YFe alloys were observed. LaFe has a well defined Tc near 275K whereas LuFe and YFe fail to exhibit well defined magnetic transitions. The bulk magnetization and the internal field are considerably higher for LaFe than for LuFe or YFe . These results suggest that the magnetic properties of the Fe depend strongly upon the size of the rare earth atom. This interpretation is supported by results for amorphous Nd‐Fe alloys which also have high Tc and large HINT since Nd also has a large atomic size.