Anisotropic magnetic properties of Zn 1– x Co x O thin films grown by pulsed laser deposition

The anisotropic magnetic and magneto-transport properties of Zn1–xCoxO thin films were investigated. By pulsed laser deposition (PLD) technique, the (0001) plane (c -plane) or (11-20) plane (a -plane) Zn1–xCoxO layer was deposited on the c -surface or r -surface sapphire substrate, respectively, and magnetization and magnetoresistance (MR) measurements were performed with magnetic fields parallel or perpendicular to the film plane. It was found that the magnitudes of the magnetization and MR were larger when magnetic fields were applied along a - or b -axis than those under magnetic fields along c -axis, irrespective of the growth orientation of the films. The consistency of the anisotropy between magnetization and MR is considered to originate from the anisotropic electronic state of Co d -electrons. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)