Angle-Dependent Inverted Hysteresis Loops in an Exchange-Biased [Co/Pt] 5 /IrMn Thin Film

The magnetization reversal processes in an exchange-biased [Co/Pt]5/IrMn multilayer thin film have been studied experimentally to analyze the existence of inverted hysteresis loops (IHLs). The magnetic properties of the sample have been investigated in detail by using vibrating sample magnetometer (VSM), magneto-optical Kerr effect (MOKE), and planar Hall effect (PHE) methods. L-MOKE measurements exhibited IHLs at some angles, while VSM data indicated conventional hysteresis loops. The existence of IHLs is explained by the competition between magnetic anisotropies within the sample. Furthermore, both L-MOKE and PHE data exhibited jumps around the hard axis loops due to the incoherent magnetization reorientations of Co layers at relatively low magnetic fields.