Formation and Perpendicular Magnetic Coupling of A1 and L10 CoPt in CoPt/TiN Films on Glass Substrate

We have studied the structure and the magnetic properties of CoPt films by using TiN spacer layer deposited on a glass substrate. We show that after annealing at 700 °C, a highly (001)-textured L10 CoPt structure has been successfully obtained. However, by increasing the annealing temperature to 800 °C, two magnetic phases A1 CoPt and L10 CoPt are formed despite of the better crystallinity of CoPt than that annealed at 700 °C. By measuring the minor magnetic hysteresis loops of the samples after applying a field cooling in a range from room temperature to 500 °C, we have further studied the magnetic coupling between A1 and L10 CoPt phases in the out-of-plane direction of the films. Our work may provide a piece of information for other studies on the heat-assisted magnetic recording.