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

这项提议要求提供资金，继续支持对无偿磁性石榴石薄膜的磁学和电学性质的调查。观察到了以氧化钇铁榴石为原型的磁性石榴石薄膜的生长，其中二价钙离子将取代三价钇离子，形成电荷不补偿材料。初步测量表明，开发新的磁性半导体材料具有令人鼓舞的潜力。特别是，在低温下观察到了光电效应，使电导率提高了六个数量级，还观察到了光电记忆效应。磁性也是不同寻常的，因为在低于150K的温度下，观察到磁矩的强烈下降。在相同的温度下，铁磁共振表明材料的内场显着增加。提出了特征能为150K的四价铁离子布居数随温度呈指数变化的模型。第二个领域涉及对铋-钍：钇铁石榴石的磁光性质的研究。具有大的角轨道动量的铊离子产生了显著的漂移，而不是通常在类Y铁石榴石材料中观察到的g=2共振条件。提出了三价铁离子可能是进一步研究铁的高级态的角动量的作用，以探索铋磁石中观察到的法拉第旋转的起源的一个很好的探针。

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.