서지주요정보
조성변조 Co/Pt 초격자 다층박막의 정특성 및 동특성 연구 = Static and dynamic properties of compositionally modulated Co/Pt multilayer thin films
서명 / 저자 조성변조 Co/Pt 초격자 다층박막의 정특성 및 동특성 연구 = Static and dynamic properties of compositionally modulated Co/Pt multilayer thin films / 김진홍.
저자명 김진홍 ; Kim, Jin-Hong
발행사항 [대전 : 한국과학기술원, 1996].
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소장정보

등록번호

8006862

소장위치/청구기호

학술문화관(문화관) 보존서고

DPH 96023

SMS전송

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초록정보

Compositionally modulated Co/Pt multilayer thin films have been attracting wide attention because of their novel properties and potential technological applications. Main goal of this study is to enhance the dynamic properties of Co/Pt magneto-optical disk by optimizing the major static parameters such as the anisotropy, the coercivity, and the Kerr effects in Co/Pt multilayer (ML). To understand major static parameters, we have investigated the dependence of the surface anisotropy in Co-based MLs on the interface roughness. We have studied the etching effects of $Si_3N_4$ underlayer on Co/Pt ML. We have analyzed the major origin of the high coercivity in Co/Pt ML on the $Si_3N_4$ underlayer prepared onto the rotating substrate. We compared the measured and calculated values of the dependence of the Kerr rotation, ellipticity, and reflectivity on the thickness of the antireflection layer. Finally, we have tested Co/Pt magneto-optical disks prepared with the optimized conditions using the results obtained from the studies of the static parameters in the Co/Pt ML. We describe the whole procedure of this work in detail. We have investigate the effects of interfacial roughness on the surface anisotropy in Co/Pt and Co/Pd ML prepared by sputtering. Degree of interfacial roughness was varied by changing Ar sputtering gas pressure from 2 to 20 mTorr for Co/Pt and 2 to 15 mTorr for Co/Pd MLs. The surface anisotropy was found to be increasing with decreasing interface roughness. We have observed that the surface anisotropy for the ML films prepared at various Ar pressure was logarithmically dependent on the integrated low-angle x-ray intensity. This logarithmic relation between surface anisotropy and integrated low-angle x-ray intensity is found to be universal in Co-based MLs. The anisotropy of Co/Pt MLs was strongly dependent on the underlayer treatment. We observed perpendicular anisotropy for Co/Pt ML prepared on the etched $Si_3N_4$ underlayer. However, Co/Pt ML prepared on the unetched $Si_3N_4$ underlayer showed In-plane. The increase of the anisotropy in Co/Pt ML on etched underlayer seemed to be caused by the the enhancement of the interface sharpness. We have found that the coercivity was increased when a Co/Pt ML on a $Si_3N_4$ underlayer was prepared onto a rotating substrate. More than four fold increase in the coercivity is thought to be due to the enhancement of domain wall pinning effects caused by an increase of surface roughness in the $Si_3N_4$ underlayer. According to the results of atomic force microscopy, the surface of the $Si_3N_4$ underlayer prepared onto the rotating substrate was rougher than that of an underlayer prepared onto a stationary substrate. We believe that the enhancement of the surface roughness is due to the oblique incidence of the sputtered materials on the rotating substrate. Co/Pt ML on dielectric antireflection for optical tunning is useful to maximize the figure-of-merit (FOM). Kerr rotation angle, ellipticity, and reflectivity of bilayer structured samples, consisting of Co/Pt ML and $Si_3N_4$ antireflection layer, were compared with the calculated results. Fairly good fitting was obtained between measured and calculated results for the samples of (5-A Co/9-A Pt) with 9-bilayer ML on the antireflection layer varying thickness of 280-570 A. Co/Pt disks were prepared and tested using a dynamic tester at 780 nm wavelength. Carrier-to-noise ratio (CNR) was increased with decreasing sputtering Ar pressure in preparation of disks. We have observed that the CNR and the FOM showed a linear relation. The CNR of 44.7 dB at ISO condition and 47.3 dB at 1 MHz frequency were obtained.

서지기타정보

서지기타정보
청구기호 {DPH 96023
형태사항 vi, 148 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Jin-Hong Kim
지도교수의 한글표기 : 신성철
지도교수의 영문표기 : Sung-Chul Shin
수록잡지명 : "High Coercivity in Co/Pt Multilayers". Japanese Journal of Applied Physics. American Institute of Physics, vol. 35, Part 1 No. 1B, pp342-345
수록잡지명 : "Interface Roughness Effects on the Surface Anisotropy in Co/Pt Multilayer Thin Films". Journal of Applied Physics, Accepted at June 1996
학위논문 학위논문(박사) - 한국과학기술원 : 물리학과,
서지주기 참고문헌 : p. 139-148
주제 Co/Pt 다층박막
표면 자기이방성
보자력
커회전각
캐리어대 잡음비
Co/Pt multilayer
Surface anisotropy
Coercivity
Kerr rotation
CNR
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