npsm 새물리 New Physics : Sae Mulli

pISSN 0374-4914 eISSN 2289-0041
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Article

Research Paper

New Phys.: Sae Mulli 2019; 69: 1135-1140

Published online November 29, 2019 https://doi.org/10.3938/NPSM.69.1135

Copyright © New Physics: Sae Mulli.

Deposition Temperature-dependent Magnetic and Structural Property Variations of Co Films

Gongin LEE1, Tae-Seong JU1, Seojin YANG1, Sehwan SONG1, Jiwoong KIM1, Sungkyun PARK*1, Eun-Young KIM2

1Department of Physics, Pusan National University, Busan 46241, Korea

2Department of Physics, Chonbuk National University, Jeonju 54896, Korea

Correspondence to:psk@pusan.ac.kr

Received: July 18, 2019; Revised: September 10, 2019; Accepted: September 11, 2019

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

A series of Co films deposited on Al$ _{2}$O$ _{3}$(0001) substrates by using DC magnetron sputtering at various deposition temperatures. For the films deposited at temperatures above 200$^{\circ}$C, the crystallinity was observed from X-ray diffraction measurements even though distinguishing between the hcp and the fcc structures was difficult. The surface roughness increased while the crystallinity improved as the deposition temperature was increased. The rocking scan also revealed improved mosaicity as the deposition temperature was increased. In-plane magnetization measurements using magneto-optic Kerr effects exhibited the unusual anisotropic behaviors of the coercivity for the films with high crystallinity. However, the saturation magnetization increased with increasing deposition temperature, indicating that the saturation magnetization was closely correlated with the crystallinity of the film.

Keywords: Cobalt, Deposition temperature, Crystallinity, Magnetic anisotropy

DC 마그네트론 스퍼터링 방법을 이용하여 Al$ _{2}$O$ _{3}$(0001) 기판 위에 증착 온도(RT, 100, 200, 300, 400, 500, 600$^{\circ}$C)에 따라 Co 박막을 제작하였다. 200$^{\circ}$C 이상에서 증착된 박막은 X-선 회절 측정 ($\omega/2\theta$ 측정)으로부터 결정성을 확인할 수 있었다. 또한, 증착 온도가 증가함에 따라 향상된 결정성으로 인한 mosaicity의 감소도 $\omega$-rocking 측정으로부터 확인할 수 있었다. 하지만, 성장된 결정면으로부터 hcp- 또는 fcc-Co상을 명확하게 구별하기 어려웠다. 자기-광학 Kerr 효과를 이용한 면 방향 자화 측정으로부터 높은 결정성을 갖는 박막은 보자력의 이방성을 가지는 것을 확인하였다. 반면, 포화자화값은 증착온도가 증가할수록 증가하였다. 따라서 포화자화값 증가는 결정성 향상과 상관관계가 높은 것으로 여겨진다.

Keywords: Cobalt, 증착온도, 결정성, 자기이방성

Figures

Fig. 1. Angular dependence of the coercivity, obtained from L-MOKE loop of Co films, deposited at various temperatures. Zero degrees set to be the maximum in-plane coercivity.

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