Magnetocrystalline Anisotropy of SrRuO3

Magnetocrystalline anisotropy in SrRuO 3 is measured by a torque magnetometer using a single-crystal sample. It is found that it has a large amount of magnetic anisotropy. ( K 1 =6.35×10 6 , K 2 =(-)10.8 4 ×10 6 and K 3 =5.33×10 5 erg/cm 3 at 4.2 K.), where the anisotropy energy is expressed as, {aligned} EK{=}K₁cos²θ+K₂cos⁴θ+K₃sin⁴θcos²φsin²φ. {aligned} The a - and b -axes of the crystal are two easy axes of magnetization, but the c -axis is only a stable direction of magnetization in a magnetic field. Torque curves observed (in the (010) and (110) planes) are rather unusual, but are analyzed by a `partially rotatable magnetization vector' model. Temperature variations of K 1 , K 2 , and K 3 were also investigated. Some possible origins of the large anisotropy in SrRuO 3 are suggested.