Thermal Stability of CoFe/Cu/CoFe/IrMn Top Spin Valve

We present a study of thermal stability of the top spin valve with a structure of seed Ta (5nm)/Co₇₅Fe₂₅ (5nm)/Cu (2.5nm)/Co₇₅Fe₂₅ (5nm)/Ir₂₀Mn₈₀ (12nm)/cap Ta (8nm) deposited at room temperature by magnetron sputtering. A vibrating sample magnetometer fixed with a heater was used to record the magnetic hysteresis loops at variational temperatures and x-ray diffraction was performed to characterize the structure of the multilayer. The exchange field H_ex and the coercivity of the pinned CoFe layer H_cp decrease monotonically with increasing temperature. The coercivity of the free CoFe layer H_cf in the spin valve shows a maximum at 498K. The temperature dependences of H_ex, H_cp and H_cf have also been discussed.