Structure and Magnetic Properties of Cr/SmCo5/Pt/Co20Fe60B20/Al Multilayer Thin Film

Structural and magnetic properties of a nanostructured Si-substrate/Cr/SmCo5/Pt/CoFeB/Al multilayer film have been investigated. SmCo5/CoFeB bilayer thin film is a very potential candidate for exchange spring magnet system. To improve the interface quality of soft magnetic CoFeB layer and hard magnetic SmCo5 layer, a very thin layer of Pt spacer layer has been introduced in between the two magnetic layers. Interface quality plays a crucial role in the performance of exchange spring magnets. A Cr under layer was deposited on Si substrate for good adhesion of SmCo5 layer. To precisely characterize the internal structure of the multilayer sample, X-ray reflectivity (XRR) measurement was performed along with theoretical simulation using Parratt formalism. The XRR study provides information on the thickness and electron density of each layer, as well as the surface and interface roughness of the sample. The Vibrating Sample Magnetometer (VSM) measurements along both perpendicular and parallel to the sample surface have been performed to investigate the magnetic anisotropy properties of the sample. The VSM study shows that in-plane magnetic easy axis and hard axis along out-of-plane direction.