Anisotropic magnetization of RuEu1.5Ce0.5Sr2Cu2O10 (Ru-1222) thin films

A dc magnetic study is reported on c-axis oriented epitaxial thin films of RuSr2Eu1.5Ce0.5Cu2O10 (Ru-1222) on (1 0 0) SrTiO3 wafers. Magnetic measurements on 200 and 500 nm-thick films were performed with the magnetic field either parallel or perpendicular to the wafer. We found that the films order magnetically at 180 K. The easy axis of the magnetization is in the basal plane and the Ru5+ ions are in their high-spin state, as deduced from the isothermal magnetization curves at low temperatures. The anisotropy ratio was found to be 7.5. The observed results are compared to data of the Ru-1222 ceramic material.