Magnetoresistance after initial demagnetization in La0.67Sr0.33MnO3∕SrTiO3∕La0.67Sr0.33MnO3 magnetic tunnel junctions

Abstract

Magnetic tunnel junctions were fabricated from La0.67Sr0.33MnO3 (LSMO)∕SrTiO3∕La0.67Sr0.33MnO3 heterostructures. Junctions initially demagnetized at 5K with an in-plane magnetic field showed larger tunneling magnetoresistance (TMR) and sharper switching than standard TMR scans. Magnetoresistive switching from the demagnetized state was stable in fields <80G yielding a TMR of 475% and a ΔMR∕ΔH≈200%∕G. Changes in resistance achievable at <500G yielded a TMR of ≈850%. A similar TMR was seen when rotating the magnetic field from an in-plane to out-of-plane orientation. The demagnetized high resistance state may indicate that the LSMO layers preferentially choose a more efficient opposite magnetic domain alignment.