Influence of transition and rare earth elements on magnetic properties of Fe-Nb-B-M (M = Ni, Ag, Gd, Tb) bulk nanocrystalline alloys

Abstract

In this work we present magnetic properties of the (Fe80Nb6B14)1􀀀xMx (where M = Ni, Ag, Gd, Tb and x = 0:08, 0.16, 0.32) bulk nanocrystalline alloys prepared by making use of mould casting technique. The applied preparation technique is favorable to nanocrystallization of the alloys with mean diameters of crystallites ranged from about 10 nm to 30 nm. Phase identi cation reveals a formation of ternary RE2Fe14B and binary REFe2 phases dependently on the alloy composition. It was found that for the alloys with Ag addition magnetic moment of Fe atom increases from 2.26 B to 3.36 B for x = 0:08 and x = 0:32, respectively. For Ni addition this quantity decreases with increasing x due to appearing of Fe Ni (fcc) phases. For Gd, Tb additions the alloys are ferrimagnetic with compensation composition ranged between x = 0:08 and x = 0:16. The both rare earth alloying additions cause a signi cant magnetic hardening especially in the case of Tb.