서지주요정보
3% Si-Fe single crystal 자화시 방출되는 음파 측정 = Acoustic emission during magnetization in 3% Si-Fe single crystal
서명 / 저자 3% Si-Fe single crystal 자화시 방출되는 음파 측정 = Acoustic emission during magnetization in 3% Si-Fe single crystal / 김철기.
저자명 김철기 ; Kim, Cheol-Gi
발행사항 [서울 : 한국과학기술원, 1986].
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소장정보

등록번호

4103515

소장위치/청구기호

학술문화관(문화관) 보존서고

MAP 8609

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초록정보

Acoustic Emission, being produced when ferromagnetic material is magnetized, is studied. Mainly, A.E. activity, V has been measured in 3% Si-Fe single crystal with various (Bm/Bs) values and frequencies and in 3% Si-Fe polycrystal with various stresses. Magnetization of ferromagnetic material is alternated by Yoke type magnet. Maximum field intensity and frequency is 7.5 Oe and 100 Hz, respectively. A resonant type A.E. transducer having 30 KHz center frequency is used with a band pass filter (15 KHz - 45 KHz) and total amplification of MAE signal is 80 dB. From the experimental results, it is found that one burst of MAE is divided into two sub-signal centered at both side of ± Hc on B-H hysteresis loop. Increasing rate of V in case of (Bm/Bs) values over 0.7 is higher than that of (Bm/Bs) values below 0.7. For dependency of frequency, increasing rate of V is divided into three parts, the first 0 Hz - 30 Hz, the second 30 Hz - 60 Hz, and the third 60 Hz - 100 Hz. Increasing rate of V has maximum at the second part, and next at the first part, and minimum at the third part. Two dependences of V on (Bm/Bs) and frequency are nearly consistent with the published results for dependency of number of 180˚ domain wall on (Bm/Bs) and frequency. It is also observed in 3% Si-Fe polycrystal that 180˚ domain wall spacing decreases with increasing stress and separated 180˚ domains at grain boundaries are joined each other at that of above a certain stress value. For the value of stress 0 to $11.2\times10^6N/m^2$, V increases with increasing stress and above $11.2\times10^6N/m^2$, it decreases with increasing stress. In conclusion, MAE is produced through magnetomechanical coupling between spin motion of domain wall and internal lattice strain, at the moment of nucleation or annihilation of 180˚ domain wall.

서지기타정보

서지기타정보
청구기호 {MAP 8609
형태사항 [iii], 56 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Cheol-Gi Kim
지도교수의 한글표기 : 김호철
공동교수의 한글표기 : 이주천
지도교수의 영문표기 : Ho-Chul Kim
공동교수의 영문표기 : Choo-Chon Lee
학위논문 학위논문(석사) - 한국과학기술원 : 물리학과,
서지주기 참고문헌 수록
주제 Iron.
Magnetization.
Acoustic emission.
단결정. --과학기술용어시소러스
규소. --과학기술용어시소러스
철. --과학기술용어시소러스
자화. --과학기술용어시소러스
음파. --과학기술용어시소러스
Silicon.
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