New Amorphous Magnetic Materials of Fe-B-Be and Fe-B-Au

摘要

Substitution of Be for B in the amorphous binary alloy Fe sub 82 B sub 18 caused an initial increase in saturation magnetization (M/sub s/) to a maximum of 200 emu/g at 4.2K, followed by a decrease for alloys with more than 4 at. % Be. Concurrently, the Curie temperature (T/sub C/) of the Fe sub 82 B/sub 18-x/Be/sub x/ alloy decreased progressively with Be content. These changes in M/sub s/ and T/sub C/ differ from those observed in Fe-B-M' metallic glasses, where M' is another metalloid (P, C, Si or Ge). Results from Auger electron and Moessbauer spectroscopies also detected the reversal trend established by the magnetization measurements. The Auger results indicated that there is a charge. Additions of Au to Fe-B tended to increase the average Fe moment, anti mu /sub Fe/, resulting in values for anti mu /sub Fe/ at 2.20 mu /sub B/ in Fe sub 82 B sub 16 sub 5 Au sub 1 sub 5 and 2.46 mu /sub B/ in Fe sub 87 B sub 11 Au sub 2 . The ternary alloys containing Au up to 1.0 at. % displayed two crystallization stages (with products of an alpha -Fe-Au solid solution followed by Fe sub 2 B) while those with higher Au content displayed a third stage with an Au-rich solid solution as the crystallization product. Annealing of Fe sub 87 B sub 11 Au sub 2 resulted in lower M/sub s/ values, unlike the annealing effect usually observed in Fe-base metallic glasses. (ERA citation 07:047364)