Thickness effect on ferro/antiferromagnetic coupling of Co/CrMnPt systems

To investigate ferro/antiferromagnetic coupling in Co/CrMnPt layers of spin valve films, spin valve films of glass/Ta/NiFe/CoFe/Cu/Co 30 A/CrMnPt D A/Ta 30 A were made with various CrMnPt thicknesses indicated D. Shift fields of the hysteresis loop indicated Hp and coercivities indicated Hc were evaluated. With the increase of D from 150 to 1000 A, the blocking temperature increases from RT to 340 °C. By increasing the temperature, the coercivity Hc increases, peaks at around the blocking temperature and then decreases. The temperature at which Hc peaks increases with an increase of D. The maximum value of Hc decreases with the increase of D. The grain size distribution of CrMnPt was measured and temperature dependencies of Hp and Hc were calculated based on a thermal fluctuation model using the grain size distribution. Quantitatively, the calculated results agree with the experimental results. The change of temperature dependence of Hp and Hc are explained by the change of the local blocking temperature ...