Magnetic Properties of Hexagonal Close-Packed Structure Type Co–Ir Binary Alloys

The magnetic properties of Co-0∼35at%Ir alloys of the perfect hcp crystal structure type were studied by means of a magnetic balance and a pendulum-type magnetometer, and the following results were obtained; The crystal magnetic anisotropy energies of hcp type Co–Ir alloys rapidly decreased with increase in Ir concentration. The magnetic moment μ per atom in these alloys decreased linearly with increase in Ir concentration, and the concentration dependence of μ, dμ⁄dq, in the hcp alloys was −2.59 μB/Ir, being lower in absolute value than −2.95 μB/Ir in fcc type Co–Ir alloys. If the magnetic moments of Co and Ir are constant for all compositions, the magnetic moment of Ir for the hcp Co–Ir alloys is −0.87 μB, and that for the fcc Co–Ir alloys is −1.20 μB.