Spin-dependent tunneling through high-k LaAlO3

Abstract

We report on the use of the LaAlO3 (LAO) high-k dielectric as a tunnel barrier in magnetic tunnel junctions. From tunnel magnetoresistance (TMR) measurements on epitaxial La2/3Sr1/3MnO3/LAO/La2/3Sr1/3MnO3 junctions, we estimate a spin polarization of 77% at low temperature for the La2/3Sr1/3MnO3/LAO interface. Remarkably, the TMR of La2/3Sr1/3MnO3/LAO/Co junctions at low bias is negative, evidencing a negative spin polarization of Co at the interface with LAO, and its bias dependence is very similar to that of La2/3Sr1/3MnO3/STO/Co junctions. We discuss possible reasons for this behaviour.

14 pages, 3 figures

References in corpus (3)

• Spintronics: Fundamentals and applications
• Nearly total spin polarization in La2/3Sr1/3MnO3 from tunneling experiments
• Fermi surface of the colossal magnetoresistance perovskite La_{0.7}Sr_{0.3}MnO_{3}

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