[16p-D704-1~18] 10.4 Spintronics in semiconductor, topological material, superconductor, and multiferroics

▼ [16p-D704-11] Gate modulation of current in the metal-insulator transition region of La_0.67Sr_0.33MnO₃

〇Tatsuro Endo¹, Shun Tsuruoka¹, Yuriko Tadano¹, Shingo Kaneta-Takada¹, Le Duc Anh^1,2, Masaaki Tanaka^1,2, Shinobu Ohya^1,2 (1.EEIS, Univ. of Tokyo, 2.CSRN, Univ. of Tokyo)

Keywords:oxide electronics, spintronics, metal-insulator transition

Within a single perovskite oxide, transition metal cations with different valences may coexist, and at specific composition ratios, they undergo abrupt property changes or phase transitions. For example, (La,Sr)MnO₃ (LSMO) exhibits metal-insulator transition (MIT) when oxygen deficiencies are incorporated. This fact allows us to induce MIT at the intended locations of a thin LSMO layer by implementing oxygen vacancies. Recently, we formed an insulating nano-channel region by inducing the MIT in the LSMO and made a planar two-terminal spin-valve device with an extremely large magnetoresistance ratio of 140%. In this work, we report a current modulation of a nanoscale MIT channel by a gate electric field. We experimentally confirmed that the electric current decreases when the positive gate voltage is applied and reproduced the current modulation theoretically by considering the change in the tunnel barrier height induced by the carrier density modulation due to the capacitance of the STO substrate.