초록

본 연구의 대상은 급속응고에 의해 제조된 비정질 Dy-Fe-B 및 Sm-Fe-B 합금리본으로서 B이 자기적 성질에 미치는 영향에 대하여 조사하였다. 구체적으로는 낮은 온도영역에서부터 큐리온도까지 자화-온도 곡선을 구하였으며, 이러한 실험 결과를 mean field theory에 기초한 분석을 통하여 제 자기적 파라미터들을 구하였다. 특별한 연구의 초점은 이러한 자기적 파라미터들이 B 함량에 따라 변화하는 거동을 조사하였다.

Abstract ▼

1. Dy-Fe-B systemExperimental magnetization-temperature curves for melt-spun ribbons of amorphous alloys (DyO.33Fe0.67)1-xBx with x=0, 0.05, 0.1 and 0.15 (in atomic fraction) are fitted with theoretical equations based on the mean field theory in order to investigate exchange couplings between const

1. Dy-Fe-B systemExperimental magnetization-temperature curves for melt-spun ribbons of amorphous alloys (DyO.33Fe0.67)1-xBx with x=0, 0.05, 0.1 and 0.15 (in atomic fraction) are fitted with theoretical equations based on the mean field theory in order to investigate exchange couplings between constituent elements as a function of the B content. The sign of the exchange coupling between Dy and Fe is negative, indicating that the magnetization direction of Dy is antiparallel to that of Fe. The sign of the other two couplings are positive. The exchange coupling between Fe ions are greatest, while that between Dy ions is negligible. The exchange couplings between Fe ions, and between Dy and Fe increase with increasing B content, the increase of the latter being much greater than the former. Resultantly, the exchange coupling between Dy and Fe becomes about one half of that between Fe ions at the highest B content. The increase of the exchange coupling between Fe ions may be explained by the increase of the Fe-Fe separation with the increase of the B content. The total magnetization is dominated by the Dy sublattice magnetization. As the B content increases, the magnetization decreases over the whole temperature range, and the Curie temperature also decreases. 2. Sm-Fe-B systemExperimental magnetization-temperature curves for melt-spun ribbons of amorphous alloys (SmO.33Fe0.67)1-xBx with x=0, 0.01, 0.02 and 0.03 (in atomic fraction) are fitted with theoretical equations based on the mean field theory in order to investigate exchange couplings between constituent elements as a function of the B content. The sign of all the couplings are positive, indicating ferromagnetic coupling between the spins. The exchange couplings between Fe ions, and Fe and Sm are comparable to each other, but they are much greater than that between Sm ions. The high exchange coupling between Fe and Sm, which is considered to occur indirectly, is rather unexpected, but it is considered to be unique characteristics of amorphous Sm-Fe alloys. The exchange coupling between Fe ions increases with increasing B content, and this may be explained by the increase of the Fe-Fe separation with increasing B content. The exchange couplings between Fe and Sm, and Sm ions also tend to increase with increasing B content.

목차 Contents

• 제1장 서론...17
• 제2장 국내외 기술개발 현황...19
• 제3장 연구개발수행 내용 및 결과...21
• 제1절 급속응고된 비정질 Dy-Fe-B 합금리본의 자기적 거동...21
• 1. 서언...21
• 2. 실험 방법...22
• 3. 분자장 이론...22
• 4. 결과 및 고찰...25
• 5. 결언...36
• 6. 참고문헌...36
• 제2절 급속응고된 비정질 Sm-Fe-B 합금리본의 자기적 거동...38
• 1. 서언...38
• 2. 실험 방법...39
• 3. 분자장 이론...39
• 4. 결과 및 고찰...42
• 5. 결언...52
• 6. 참고문헌...53
• 제4장 연구개발목표 달성도 및 대외기여도...55
• 제5장 연구개발결과의 활용계획...57
• 부록...61