a Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
b Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
Abstract:
Tunneling magnetoresistance values above 20% and 40% were obtained for as-deposited and annealed tunnel junctions, Ta/NiFe/Cu/NiFe/IrMn/CoFe/Al-oxide/CoFe/NiFe/Ta, respectively. Exchange biasing field increased from 270 to 550 Oe after annealing resulting from sharpening of the IrMn/CoFe interface. dV/dI vs. V curves showed asymmetric profiles, which were due to asymmetry of the CoFe/Al-oxide interfaces and difference in microstructure of the CoFe layers.