Magnetic properties and domain structure of CoFeB/Pd multilayers with perpendicular magnetic anisotropy

Abstract

The magnetic properties and domain structure of (CoFeB/Pd)n (n = 2 multilayers prepared by DC magnetron sputtering with perpendicular magnetic anisotropy have been investigated systematically. The study has been carried out by using vibration sample magnetometer (VSM) and magneto-optical Kerr effect (MOKE) microscope. The results show clear changes of magnetic hysteresis and domain structure when increasing the number of bilayer (n) from 2 to 10. With increasing the number of bilayers, the multilayers’ hysteresis loops change from square to slanted shape while domain structures change from circular-like to maze. The magnetization reversal changes from easy to be fully reversed with small n to hard to be fully reversed with large n. The behavior is explainable in term of pinning effect.