Somdev Tyagi

During the last few years increased interest has been shown in investigating the amorphous magnetic alloys of transition metals with metalloids prepared by techniques other than the most widely used splat cooling technique. For example, amorphous alloys have been obtained by the spark erosion /1, 2/, gas atomization with water quenching /3/, and the capillary quenching techniques /4/. Powder samples of amorphous Fe^Si^B^g produced by the spark erosion method have recently been investigated by Berkowitz et al. /2/ using X-ray diffraction, Moss-bauer, and low and high-field magnetization measurements. The powder samples consisted of mainly spherical particles in the ranges 0.5 to 5 jam, 10 to 20 jam, and 20 to 30 jam. Compared with the Curie point, Tc = 717K for the ribbon samples obtained by the splat quenching technique, the particles show a gradual decrease in the T^ values with decreasing particle fraction size. The 0.5 to 5 jam range has T^ = 628 K as determined by the high-field magnetization data. This lowering of TQ has been interpreted as due to the decreased chemical short-range ordering (CSRO) caused by the higher quenching rates achieved by 7 6 the spark erosion technique (10 versus 10° K/s for the splat quenching method).