Synthesis and magnetic properties of PrFe12-xMox and PrFe12-xMoxNy (0.5≤x≤1.0, y≊1)

Abstract

A series of iron-rich ternary intermetallics PrFe12-xMo x (x=0.5, 0.75, 1.0) and their nitrides have been prepared by arc melting, annealing at 1273-1393 K and water quenching. A single-phase structure of the ThMn12 type has been obtained for x=1.0 when annealed at 1345 K (with α-Fe<5%). The lattice constants are a=8.5978(2) Å, c=4.7795(3) Å. The alloys exhibit planar anisotropy, a Curie temperature of 498 K, and a room-temperature magnetization of 120.4 A m2/kg prior to the nitrogenation. After nitrogenation the anisotropy changes to uniaxial, the Curie temperature increases to 681 K, and the room-temperature magnetization becomes 136 A m2/kg. A lattice expansion corresponding to 2.4% of the cell volume is observed. In the x=0.5 and x=0.75 alloys, a secondary 2:17 phase is also present, besides the 1:12-type structure. The peritectic decomposition temperature is 1393 K for all samples.