Magnetic Properties of Ba2Zn2Fe28O46 and Ba2Co2Fe28O46 Single Crystals

Abstract

The static magnetic properties of Ba2Zn2Fe28O46(ZnX) and Ba2Co2Fe28O46 (CoX) single crystals were measured as a function of field up to 15.5 kOe and temperature up to Tc. ZnX exhibits uniaxial anisotropy: EA=K1 sin2θ over the entire temperature range; Ha remains approximately constant ≈12.8 kOe over a large temperature range; Tc=705±3°K; nβ(calc) (H=∞, T=0)=60 μβ on the basis of a collinear spin model; nβ(exp) (H=∞, T=0)=50.4 μβ. The anisotropy of CoX is much more complex, requiring three terms. Below 416°K it exhibits an easy plane of magnetization. Above 416°K, EA=K1 sin2θ, Tc=740±4°K. The nβ(exp) (H=∞, T=0)=46 μβ in good agreement with nβ(calc) (H=∞, T=0)=47 μβ assuming a collinear spin model.