Hyperfine Field in Weakly Antiferromagnetic βMn Alloys

The internal field at Mn 55 in βMn alloys with impurities of several kinds was systematically investigated in antiferromagnetically ordered state. In non-transition element alloys the internal field is almost determined by the increase of the lattice constant irrespective of the species of the impurity. In a low concentration region of the transition element alloys, the internal field is expressed as the sum of two parts due to the increase of the lattice constant and the increase of the excess number of d-electrons introduced by the impurity. In a region of the high impurity concentration of transition element alloys, both contributions are no more simply additive. Equi-internal field lines are constructed in the plane of d-electron number and lattice constant, and the boundary of the magnetic and non-magnetic state is determined in βMn binary and ternary alloy systems.