Control of the perpendicular magnetic anisotropy and microstructure of L1(0)-CoPt/TiN multilayer films with the TiN layer on glass substrates

摘要

TiN(5 nm)[CoPt(4 nm)/TiN(x nm)](5) multilayer films (x = 1, 2, 4, 6, 8, 10, 14) have been deposited on glass substrates by dc magnetron sputtering, and a L1(0)-CoPt structure with perpendicular magnetic anisotropy (PMA) has been obtained after annealing at 700 and 800 degrees C. It is found that changing the TiN layer thickness and annealing temperature significantly affects the ordering degree and magnetic anisotropy energy of L1(0)-CoPt/TiN multilayer films. To obtain the maximum value of the ordering degree and magnetic anisotropy energy, the optimum thickness of the TiN layer is around 4 and 8 nm, with an annealing temperature of 700 and 800 degrees C, respectively. Structural characterization results have shown that the thickness of the TiN layer greatly affects the interface structure between CoPt and TiN layers. When TiN layer thickness is below 2 nm, it tends to be discontinuous after annealing, which results in the coalescence of the adjacent CoPt layers. When TiN layer thickness is above 8 nm, the interface roughness becomes larger. In such cases, the preferred orientation, ordering degree of the L1(0) structure and the PMA of the films will be impaired.