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Synthesis of epitaxial ferrimagnetic NiCo<sub>2</sub>O<sub>4</sub> thin films on SrTiO<sub>3</sub> and Sr<sub>3</sub>Al<sub>2</sub>O<sub>6</sub> buffered SrTiO<sub>3</sub> substrates

ORAL

Abstract

The inverse spinel NiCo2O4 (NCO) is ferrimagnetic with high Curie temperature (TC) and spin polarization. It is of high research interest to integrate it with other functional oxides, while many of them have the perovskite structure. We investigated the effects of a perovskite substrate on the magnetotransport properties of NCO by depositing 30 nm NCO thin films on SrTiO3 (STO) and Sr3Al2O6 (SAO) buffered STO substrates using off-axis RF magnetron sputtering. Both types of samples exhibit insulating behavior below 300 K, and the films on SAO buffered STO shows more than 10 times higher resistivity at 300 K. We estimated the TC from the magnetoresistance hysteresis. These samples show TC of up to 150 K, well below that for films deposited on MgAl2O4 substrates (above 300 K). The reduced TC can be attributed to a high density of anti-phase boundaries due to the structural mismatch between NCO and STO. We also discuss the possibility of suspending the NCO thin films by water etching the SAO buffer layer.

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Presenters

  • Qiuchen Wu

    Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln

Authors

  • Qiuchen Wu

    Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln

  • Le Zhang

    Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln

  • Yifei Hao

    University of Nebraska - Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln

  • Xia Hong

    University of Nebraska - Lincoln, Department of Physics and Astronomy & Nebraska Center of Materials and Nanoscience, University of Nebraska - Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln