Epitaxial growth and magnetic characterization of ferromagnetic Co_4N thin films on SrTiO_3(001) substrates by molecular beam epitaxy

摘要

We have attempted to grow single-crystalline Co_4N thin films on SrTiO_3 (STO)(001) substrates by molecular beam epitaxy by the simultaneous supply of 3N-Co and radio-frequency NH_3 plasma. Reflection high-energy electron diffraction and 6-2$ X-ray diffraction patterns confirmed that the epitaxial growth of Co_4N films was successfully achieved. X-ray φ-scan measurements using Co_4N(301) and STO(301) diffractions revealed that the epitaxial relationship between Co_4N and STO was a cube-on-cube type. Magnetization versus magnetic field curves measured at room temperature for Co_4N epitaxial layers covered with a Au capping layer using a vibrating sample magnetometer showed that Co_4N[110] is the axis of easy magnetization.