金属-金属颗粒膜巨磁电阻效应的尺寸效应

The Effect of Granular Size on the Giant Magnetoresistance in Ferromagnetic Metal-Non-Magnetic Metal Granular Films

按照颗粒尺寸将颗粒膜中磁性颗粒分为3类:单畴超顺磁颗粒、单畴铁磁性颗粒和多畴磁性颗粒.不同尺寸的磁性颗粒对巨磁电阻效应作用的研究存在着争议.为此,该文假设颗粒膜中磁性颗粒尺寸呈对数正态函数分布,利用二流体模型和有效媒质理论对颗粒膜的巨磁电阻效应进行了研究.计算结果表明,以单畴铁磁性颗粒为主导作用的理论计算结果与相关各类实验相符,表明单畴铁磁性颗粒对颗粒膜的巨磁电阻效应起主导作用.

Based on the facts that the size distribution of magnetic granule is unavoidable in granular films, we divided all the magnetic granules in the granular films into three categories： superparamagnetic granules single domain ferromagnetic granules and multi - domain magnetic granules. They have different contribution to giant magnetoreisistance effect, which have been in dispute for a long time. To clarify this dispute, assumingthat the particle size satisfied with lognormal function distribution, we combined effective medium theory with the two - channels conducting model to study giant magnetoresistance in granular films. The calculated results indicated that single domain ferromagnetic granules play a key role in giant magnetoresistance.