Exchange bias in BiFeO3/CoFe2O4 heterostructure

ORAL

Abstract

Room temperature multiferroics BiFeO3 (BFO), both ferroelectric and antiferromagnetic, has been extensively investigated as a part of exchange bias structures since it promises the electrical field control over the exchange bias. This work focuses on the exchange interaction between ferromagnet CoFe2O4 (CFO) and BFO. Bilayer films CFO and BFO were first grown on SrTiO3 (STO) by Pulsed Electron Deposition (PED) and then field cooled in magnetic field. XRD showed single phase CFO and BFO were grown epitaxially on STO single crystal substrates, and the typical thickness was 21nm for BFO and 3.6$\sim $18nm for CFO. In the bilayer structure, we observed that the coercive field increased 100{\%} at 300K and 30 {\%} at 50K, comparing to these of CFO single layer. Also in the bilayer structure, a noticeable exchange bias field (Hex) increased from $\sim $30 Oe at 300 K to $\sim $ 60 Oe at 50 K. We will discuss the impact of the film thickness and the roughness of interface on exchange bias.

–

Authors

  • Yonghang Pei

    Physics Department, University of Virginia

  • Jiwei Lu

    Materials Science Department, University of Virginia, Department of Materials Science and Engineering, University of Virginia, Materials Science and Engineering Department, University of Virginia, University of Virginia

  • Ryan Comes

    Department of Materials Science and Engineering, University of Virginia

  • Stu Wolf

    University of Virginia, Physics Department, University of Virginia