Magnetocrystalline anisotropy of light rare-earth cobalt compounds

Abstract The magnetocrystalline anisotropy constants of Y-, Ce-, Pr-, Nd-, Sm- and CeMMCo 5 were determined from magnetization and torque curve measurements on single crystals in the temperature range between 77 K and the ferromagnetic Curie point and in fields up to 16 kOe. The anisotropy of Y-, Ce-, Sm- and CeMMCo 5 can be described by the constant K 1 alone, whereas K 2 and K 4 are necessary for NdCo 5 and PrCo 5 , for temperatures below 300 K. A comparison of the temperature dependence of K 1 with the classical temperature dependence of magnetocrystalline anisotropy shows that the intrinsic anisotropy itself is a function of temperature. The change in type of anisotropy from NdCo 5 and PrCo 5 is consistent with crystal field calculations.