Tunneling magnetoresistance at up to 270 K in La0.8Sr0.2MnO3/SrTiO3/La0.8Sr0.2MnO3 junctions with 1.6-nm-thick barriers

Abstract

Magnetic tunneling junctions are fabricated from epitaxially grown ${\mathrm{La}}_{\mathrm{0.8}}{\mathrm{Sr}}_{\mathrm{0.2}}{\mathrm{MnO}}_{\mathrm{3}}{\mathrm{/SrTiO}}_{\mathrm{3}}{\mathrm{/La}}_{\mathrm{0.8}}{\mathrm{Sr}}_{\mathrm{0.2}}{\mathrm{MnO}}_{\mathrm{3}}$ trilayers. A large tunneling magnetoresistance of 150% is observed for a junction with a thin barrier layer (1.6 nm) under a low switching field (<10 Oe) at 5 K. A small tunneling magnetoresistance is observed even at 270 K, which is close to the ferromagnetic Curie temperature (290 K) of the ${\mathrm{La}}_{\mathrm{0.8}}{\mathrm{Sr}}_{\mathrm{0.2}}{\mathrm{MnO}}_{\mathrm{3}}$ film. The large magnetoresistance and high operating temperature are attributed to the sufficiently thin and uniform barrier layer of ${\mathrm{SrTiO}}_{\mathrm{3}}.$