Uniaxial Magnetic Anisotropy Induced in Pt–Co Alloy by Tempering under Stress

When the 50 at.% Pt–Co alloy is tempered under compressive stress, a uniaxial magnetic anisotropy is induced which has its easy axis along the direction of the stress. When tempered under tensile stress instead of compression, the anisotropy has its hard axis along the direction of the stress. This anisotropy is most developed in the so‐called over‐aged (perfectly ordered) state, and K=3.1×10⁶ erg/cc is measured in the field of 20 kOe. 4πI=7.4 kG and 4.7 kG are measured in the field of 23 kOe along the easy and the hard axis, respectively. From x‐ray‐diffraction diagrams a kind of fiber structure is observed in which the $\text{〈001〉}$ axes of the ordered tetragonal lattices are oriented to the direction of the compressive stress somewhat more than the cross directions.