Effect of "dipolar-biasing" on the tunability of tunneling magnetoresistance in transition metal oxide systems

Abstract

We observe an unusual tunneling magnetoresistance (TMR) phenomenon in a composite of La 2/3Sr 1/3MnO 3 with CoFe 2O 4 where the TMR versus applied magnetic field loop suggests a negative coercive field. Tracing its origin back to a dipolar-biasing of La 2/3Sr 1/3MnO 3 by CoFe 2O 4, we show that the TMR of even a single composite can be tuned continuously so that the resistance peak or the highest sensitivity of the TMR can be positioned anywhere on the magnetic field axis with a suitable magnetic history of the sample. This phenomenon of an unprecedented tunability of the TMR should be present in general in all such composites. © 2012 American Institute of Physics.