Magnetoresistance after initial demagnetization in La0.67 Sr0.33 Mn O3 SrTi O3 La0.67 Sr0.33 Mn O3 magnetic tunnel junctions

Magnetic tunnel junctions were fabricated from La0.67 Sr0.33 Mn O3 (LSMO) SrTi O3 La0.67 Sr0.33 Mn O3 heterostructures. Junctions initially demagnetized at 5 K 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 <80 G yielding a TMR of 475% and a ΔMRΔH≈200%G. Changes in resistance achievable at <500 G 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.