MAGNETIC PROPERTIES OF AN EQUI-ATOMIC PTCO SINGLE CRYSTAL HAVING A [111] ORIENTATION

The equi-atomic alloy of PtCo (77 wt% Pt, 23 wt% Co) is a high energy product, high coercive force permanent magnet material. Polycrystalline magnets of PtCo are isotropic. Measurements of the intrinsic coercive force as a function of crystallographic orientation made on a small PtCo single crystal showed it to be anisotropic. The maximum Hci value was found to occur in the 〈111〉 direction. Subsequently, a larger single crystal was produced in the form of a right circular cylinder for the purpose of making B-H measurements in the [111] direction. Values were obtained for Br, Hc, Hci, and (BH)max from hysteresis graphs of both the single-crystal PtCo magnet with a [111] orientation and the conventional isotropic polycrystalline PtCo magnet. Values measured were: B r Hc Hci (BH)max Single crystal 〈111〉 6500 5900 8200 9.8×106 Polycrystalline 6400 5500 7500 9.2×106. © 1969 The American Institute of Physics.