Directional solidification and densification of permanent magnets having single domain size MnBi particles

A method for producing a permanent magnet, comprising the steps of:

• directionally solidifying a composition containing Mn and Bi in a liquid and MnBi and Bi in a resulting solid composition, said solid composition containing from 0.1 to 50% by atomic fraction Mn at a solidyfing rate of 0.5 cm/hr to 100 cm/hr and at a thermal gradient, in the liquid at the liquid-solid interface, of from 10.degree. C./cm to 1000.degree. C./cm so that there is in the solid an aligned array of magnetic signal domain size MnBi particles;
• post heat treating the solid composition in a temperature range of from 200.degree. C. to 260.degree. C. for a period of from 1 to 100 hours so that the particles have substantially the theoretical maximum remanent induction of 8200 gauss and intrinsic coercivity of 35,000 Oe;
• and
• increasing volume fraction of the McBi particles in the solid composition to substantially full density by hot rolling or extruding.