Effect of in-situ annealing temperature on magnetic domain structure and magnetism of Zr2Co11 thin films

Rhombohedral Zr2Co11-based materials have shown very promising magnetic properties, but this rhombohedral phase is elusive and metastable. In this study, nanocrystalline Zr2Co11 films were obtained by magnetron co-sputtering on Si (100) substrate with the in-situ annealing. Temperature dependence of magnetic domain structure and magnetic properties of nanocrystalline Zr2Co11 have been investigated. Proper in-situ annealing temperature enhances the content of hard magnetic phase and improves the magnetic properties. Compared with Zr2Co11 thin films grown at low temperature (823 K) and higher temperatures, thin films with in-situ annealing temperature of 1023 K have coercivity Bc (Bc = μ0Hc) of 0.15 T and energy product BHmax of 16.0 kJ/m3. Magnetic Force Microscopy images show the highest bright-dark magnetic domain contrast with highest root-mean-square values of the phase shift for thin film with in-situ annealing temperature of 1023 K. These findings have correlated magnetic domain structure and magnetic properties of Zr2Co11 thin films, and elaborated the effect of different in-situ annealing temperatures on magnetic domain structure.