Large magnetoresistance and temperature-driven spin filter effect in spin valve based on half Heusler alloy

Abstract

High spin-injection-efficiency (SIE) and thermal spin-filter-effect (SFE) from a magnetic material to a barrier material is crucial to the high performance of spintronic device and spin caloritronic device, respectively. By performing nonequilibrium Green's function combined with first principles calculations, we study the voltage-driven and temperature driven spin transport properties of half Heusler alloy RuCrAs based spin valve with different atom-terminated interfaces. The spin valve with CrAs-top (or Ru-top) interface structure has ultrahigh equilibrium MR ratio of ~1.56×109% (or ~5.14×108%), ~100% SIE, large MR ratio and high spin current intensity under bias voltage, suggesting that it has a great potential application in spintronic devices. The spin valve with CrAs-top (or CrAs-bri) interface structure has a perfect SFE due to its very high spin polarization of temperature-driven currents, and it is useful in spin caloritronic device.