NMR Study of Antiferromagnetic γ Mn Alloys

Abstract

NMR study has been made on various antiferromagnetic β-Mn alloys at liquid helium temperatures. The alloys used are β-Mn with Ti, V, Cr, Fe, Co, Ni, Ru, Rh, Pd, Ir, Al, Si, Zn, Ga, Ge, In and Sb impurities. The interatomic distances of these alloys have been also measured by X-ray diffraction. Several β-Mn alloys become antiferromagnetic at 4.2 K by an addition of small amount of impurity metal. The magnetic moment on Mn is assumed to be less than 0.5 µ B . In β-MnCo alloys, the magnetic moment of Co is estimated to be about 1.0 µ B . The magnetic ordering of β-Mn alloys with non-transition metal impurities is attributed to the lattice expansion. In the case of transition metal impurities, the lattice expansion, the change of the number of d-electrons and the induction of the magnetic moments of Mn by the localized moment on impurity atom must be considered.