FERROMAGNETISM AND ORDER IN NICKEL MANGANESE ALLOYS

Abstract

An investigation of ferromagnetism in nickel manganese alloys containing up to 40 atomic per cent manganese has been carried out. Twenty alloys within this composition range were subjected to heat treatments such that the atomic arrangement within the alloys varied from disorder to a high degree of long range order.The degree of order of Ni3Mn calculated from measured saturation magnetization using the atomic model of ferromagnetism was consistent with the value calculated from the ratio of measured integrated intensity of the (110) X-ray diffraction superlattice line to that of line (111).The relationship between saturation magnetization and concentration for the disordered alloys can be explained adequately by the existence of short range order. A value of 3.4 Bohr magnetons for the effective magnetic moment of manganese atoms in a nickel lattice was deduced.