Room-temperature spontaneous perpendicular exchange bias in IrMn/[Co/Pt]3 multilayers

Perpendicular exchange bias (PEB) is highly desirable for the development of advanced nanoscale spintronics devices. The attainment of conventional PEB typically involves a field-cooling process through the Néel temperature of antiferromagnetic materials. In this study, we demonstrated the realization of spontaneous PEB (SPEB) in IrMn/[Co/Pt]3 multilayers utilizing isothermal crystallization of IrMn at room temperature (RT). And the SPEB generated isothermally at IrMn/Co interface does not destroy the perpendicular magnetic anisotropy of the multilayers. The magnetic domains of the multilayers captured by Kerr microscopy after different magnetization time also indicate the generation of SPEB. The magnitude of SPEB can be controllable by varying the isothermal magnetization time and the annealing temperature of IrMn. The relationship between magnetization waiting time and SPEB reveals that even slight isothermal crystallization can generate substantial SPEB. Our results provide an alternative approach to isothermally generate PEB in IrMn/[Co/Pt]3 multilayers at RT.