Measurement of the Interfacial Spin Polarization of La_0.7Sr_0.3MnO₃ Film by Andreev Reflection

Abstract

To develop a new versatile technique for determining the interfacial spin polarization of ferromagnetic materials, we examined Andreev reflection measurements by using superconducting NbN junctions. In this article, we report measurements and analysis of spin polarization of La_0.7Sr_0.3MnO₃ film at the interface. We found that the spin polarization of La_0.7Sr_0.3MnO₃ film strongly depends on the cooling condition of La_0.7Sr_0.3MnO₃ film after deposition. The maximum spin polarization of La_0.7Sr_0.3MnO₃ film was 0.77 ± 0.02.