Effects of Annealing Conditions on Magnetic Properties of Ni81Fe19/Ir20Mn80 Exchange Biased Thin Films

Abstract

The Ni₈₁Fe₁₉/Ir₂₀Mn₈₀ bilayer was grown using DC sputtering. After magnetic field cooling under an external magnetic field of 50 kOe, the room-temperature magnetic properties were investigated using a resonance-vibrating sample magnetometry.  The exchange bias field and coercive field were determined from hysteresis loops, and no training effect was observed during the remagnetization process. Effects of annealing conditions on magnetic properties of the exchange biased thin film was investigated. The exchange bias field decreases with increasing annealing temperature, while the saturation magnetic moment is rather constant before dramatically decreasing at a critical annealing temperature. Saturation magnetic moment and exchange bias field of the exchange biased thin film strongly depend on phase transformation of ferromagnetic layer during the annealing process.