pISSN 0374-4914 eISSN 2289-0041

Research Paper

New Physics: Sae Mulli 2013; 63: 1328-1332

Published online December 31, 2013 https://doi.org/10.3938/NPSM.63.1328

Post-annealing-temperature-dependent Magnetic Anisotropy of CoFe$_2$O$_4$ Thin Films

D. Y. LEE1, C. -W. CHO1, S. H. LEE1, J. W. KIM1, H. K. KIM1, M. Y. LEE1, J. S. LEE1, S. PARK*1, S. M. HWANG2

1Department of Physics, Pusan National University, Busan 609-735, Korea
2Pohang Accelerator Laboratory, Pohang University of Science & Technology, Pohang 790-834, Korea

Correspondence to:

psk@pusan.ac.kr

Received: October 29, 2013; Revised: November 20, 2013; Accepted: December 11, 2013

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

CoFe$_2$O$_4$ thin films with magnetic anisotropy were deposited by RF sputtering at room temperature and were post-annealed at various temperature to examine the annealing-temperature-dependent structural and magnetic characteristics of the films. X-ray diffraction measurements showed the as-grown sample and the samples annealed at temperatures below 700 $\,^{\circ}\mathrm{C}$ exhibited non-crystalline phases even though magnetic hysteresis loops (not superparamagnetic behavior) appeared for the film annealed at 500 $\,^{\circ}\mathrm{C}$. With further increases in the annealing temperature, the in-plane anisotropy and the grain size increased, and crystallinity improved. Furthermore, the coercivity and the remanent magnetization also increased with increasing post-annealing temperature. These increases were associated with the increased crystalline size and the improved crystallinity of the films.

Keywords: Spinel structure, Magnetic anisotropy, Post-annealing