Nearly total spin polarization in La2/3Sr1/3MnO3 from tunneling experiments

TL;DR

This study demonstrates nearly complete spin polarization in La2/3Sr1/3MnO3 using tunneling experiments, highlighting its potential as a highly effective spin analyzer and confirming its half-metallic nature.

Contribution

The paper reports a record high magnetoresistance ratio and spin polarization in La2/3Sr1/3MnO3 tunnel junctions, showing improved performance through optimized fabrication techniques.

Findings

Magnetoresistance ratio exceeds 1800% at 4K

Electrode spin polarization is at least 95%

High magnetoresistance persists above 270K

Abstract

We have performed magnetotransport measurements on La2/3Sr1/3MnO3 / SrTiO3 / La2/3Sr1/3MnO3 magnetic tunnel junctions. A magnetoresistance ratio of more than 1800 % is obtained at 4K, from which we infer an electrode spin polarization of at least 95 %. This result strongly underscores the half-metallic nature of mixed-valence manganites and demonstrates its capability as a spin analyzer. The magnetoresistance extends up to temperatures of more than 270K. We argue that these improvements over most previous works may result from optimizing the patterning process for oxide heterostructures.