Magnetic Domain Wall Resonance and the Electric Field Shift of the Ferromagnetic (Materials Research)

磁畴壁共振和铁磁体的电场位移（材料研究）

• 批准号: 8620109
• 负责人: Philip Wigen
• 金额: --
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1988-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8620109&HistoricalAwards=false
• 关键词: Magnetic; Domain; Wall; Resonance; Electric

This proposal requests funds for continued support of investigations into the magnetic and electrical properties of uncompensated magnetic garnet films. It has been observed that thin films of the magnetic garnets, of which the prototype is yttrium iron garnet can be grown in which the divalent calcium ion will substitute for the trivalent yttrium ion forming a charge uncompensated material. Preliminary measurements show encouraging potential for the development of new magnetic semiconductor materials. In particular, at low temperatures a photo-electrical effect has been observed that enhances the conductivity by six orders of magnitude and a photomemory effect is also observed. The magnetic properties are also unusual in that a strong decrease of the magnetic moment is observed at temperatures below 150 K. At this same temperature the ferrromagnetic resonance indicates a significant increase in the internal fields of the materials. A model has been proposed in which the population of the quadruvalent iron ion varies exponentially with temperature having a characteristic energy of 150 K. The second area involves an investigation into the magneto- optical properties of bismuth-thullium: yttrium iron garnet. The thullium ion with it's large angular orbital momentum produces a significant shift from the g=2 resonance condition normally observed in the yttrium iron garnet like materials. It is proposed that trivalent iron ion might be an excellent probe to further investigate the role of the angular momentum of the higher order states of iron to investigate the origin of the Faraday rotation observed in bismuth magnetic garnets.

本提案要求资金继续支持对未补偿的磁性石榴石薄膜的磁性和电学性质的研究。以钇铁石榴石为原型的磁性石榴石可以生长成薄膜，薄膜中二价钙离子取代三价钇离子形成电荷不补偿材料。初步测量结果显示，新型磁性半导体材料的发展具有令人鼓舞的潜力。特别是，在低温下，已经观察到光电效应，电导率提高了6个数量级，并且还观察到光记忆效应。磁性能也很不寻常，在温度低于150 K时，磁矩明显下降。在相同的温度下，铁磁共振表明材料的内部磁场显著增加。提出了四价铁离子的居布率随温度呈指数变化的模型，其特征能为150 K。第二个领域涉及对铋-铥-铁石榴石的磁光性质的研究。具有大角轨道动量的铥离子与通常在类钇铁石榴石材料中观察到的g=2共振条件产生了显著的变化。本文提出，三价铁离子可能是进一步研究铁高阶态角动量在研究铋磁性石榴石中观察到的法拉第旋转起源中的作用的一个很好的探针。