Coercivity Mechanisms in Nanocrystalline Sm–Co–Cu Thin Films: the Spring Effect

In magnetron sputtering, with the simultaneous deposition of SmCo and copper, it is possible for tailoring the coercive field of SmCoCu thin films. Microstructural analysis pointed out that nanocrystalline 2:17 rhombohedral phase with diameter 10–100 nm was obtained, and coercivities in the range between 3 and 8.5 kOe. These characteristics are suitable for magnetic recording. The coercivity mechanisms are discussed. The initial magnetization curve, measured in thermally demagnetized samples, is used to discuss the coercivity mechanisms. A spring effect in the samples is observed. The spring effect is due to reversible rotation of magnetization and indicates that the coercivity mechanism is nucleation or coherent rotation of single domain size nanoscale grains. Structural data refined with X-ray diffraction Rietveld analysis for Sm 2 (Co,Cu) 17 rhombohedral phase, Sm(Co,Cu) 5 phase and cubic oxide Sm 2 O 3 phase are provided.