서지주요정보
천이금속계 다층박막의 스트레스 및 자기변형 연구 = Stress and magnetostriction in transition metal based magnetic multilayers
서명 / 저자 천이금속계 다층박막의 스트레스 및 자기변형 연구 = Stress and magnetostriction in transition metal based magnetic multilayers / 김영석.
저자명 김영석 ; Kim, Young-Seok
발행사항 [대전 : 한국과학기술원, 1999].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8010030

소장위치/청구기호

학술문화관(문화관) 보존서고

DPH 99009

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

We have developed a delicate method for the determination of stress and magnetostriction coefficient in magnetic multilayer films, to clarify the contribution of magnetoelastic anisotropy to the perpendicular magnetic anisotropy(PMA) observed in these systems. In the fields of a study on ultrathin magnetic films, magnetic multilayers showing room-temperature perpendicular magnetic anisotropy have been of particular interests because of their novel properties and potential technical applications. Various explanations for the PMA have been suggested for the magnetic multilayers, such as interface anisotropy as a consequence of the reduced symmetry and enhanced magnetocrystalline anisotropy due to altered electronic structure. Magnetoelastic anisotropy, which is expressed by the product of stress and magnetostriction, was often refered as a possible source of PMA, but it was seldom measured accurately because of the difficulty of the measurements, nor was it referred as a main origin of PMA. For the determination of stress, we have developed a ultrahigh sensitive in situ stress-measurement apparatus of thin films using an optical non-contact displacement detector. A change of the gap distance between the detector and the substrate, caused by stress of a deposited film, was detected by a corresponding change of the reflectivity. The highest sensitivity of the displacement detector was reached to 134mV/㎛ with the aid of computer simulation. The apparatus was applied to in situ stress measurements of several multilayers of Co/Pt, Ni/Pd, and Ni/Pt prepared on the glass substrates by dc magnetron sputtering. The detector turned out to be sensitive enough to observe the coherent-to-incoherent transition within submonolayer deposition in the matching planes of the multilayers. The coherent-to-incoherent transition was confirmed by the cross-section TEM pictures for Co/Pt multilayers. We also found that this powerful tool could demonstrate the incipient behavior of stress due to the difference of surface free energies between two dissimilar materials at the interface. With the same apparatus, we achieved a high resolution of $3\times10^{-7}$ in the measurement of magnetostriction coefficient, which is sensitive enough to observe the surface magnetostriction effect in Co/Pd, Co/Pt, and Ni/Pt multilayers. By applying this method to several multilayer systems, we could explain the role of magnetoelastic anisotropy in these systems. In particular, we found that the magnetoelastic anisotropy was the major origin of the observed PMA in Ni/Pt multilayers for the first time. Futhermore, by changing the stress state in Ni sublayer with changing the Ar sputtering pressure, we firstly demonstrate that the magnetic anisotropy can be artificially engineered for the Ni/Pt multilayers with the same composition. In summary, we have studied the magnetoelastic anisotropy in Co- and Ni-based multilayers for clarifying its contribution to PMA in these system. Using the high sensitive optical detector, we could observe the variation of stress and magnetostriction with an atomic-layer sensitivity. In Ni/Pt multilayers we found that the magnetoelastic anisotropy was the main origin of PMA, and using this fact the magnetic anisotropy could be manipulated via stress-engineering for the first time.

서지기타정보

서지기타정보
청구기호 {DPH 99009
형태사항 v, 107 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Young-Seok Kim
지도교수의 한글표기 : 신성철
지도교수의 영문표기 : Sung-Chul Shin
수록 잡지명 : "Role of magnetoelastic anisotropy in Ni/Pt multilayer films". IEEE Transactions on Magnetics. The IEEE Magnetics Society, vol. 34, no. 4, pp. 858-960
수록 잡지명 : "Observation of perpendicular magnetic anisotropy in Ni/Pt multilayers at room temperature". Applied Physics Letter. American Institute of Physics, vol. 73, no. 3, pp. 393-395
수록 잡지명 : "In situ stress measurements of Co/Pd multilayer films using an optical non-contact displacement detector". Thin Solid Films. Elsevier Science, vol. 258, pp. 128-131
수록 잡지명 : "Magnetoelastic effect in Co/Pd multilayer films". Journal of Applied Physcis. American Institute of Physics, vol. 76, no. 10, pp. 6087-6089
학위논문 학위논문(박사) - 한국과학기술원 : 물리학과,
서지주기 참고문헌 : p. 102-107
주제 스트레스
자기변형
다층박막
자기탄성 이방성
천이금속
Stress
Magnetostriction
Multilayers
Magnetoelastic anisotropy
Transition metal
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