纳米磁性颗粒点阵的磁电阻效应  

Magnetoresistance in dot array of nanosized magnetic particles

作　　者：章雯[1] 吕冬丽[2] 

机构地区：[1]苏州工业职业技术学院电子工程系,江苏苏州215011 [2]苏州大学物理科学与技术学院,江苏苏州215006

出　　处：《苏州大学学报（自然科学版）》2010年第4期57-60,共4页Journal of Soochow University(Natural Science Edition)

基　　金：江苏省教委基金(06KJD140165)

摘　　要：纳米颗粒高密度排列体系有其独特的磁学和电输运性质.主要研究了具有单轴各向异性的单畴磁性颗粒二维正方点阵的磁性和隧穿磁电阻效应.纳米磁性颗粒规则地浸在绝缘基质中.自旋电子在点阵中的输运主要来源于隧穿磁电阻.颗粒磁矩的取向与隧穿磁电阻的大小直接相关.我们发现磁偶极矩相互作用的强弱及温度对该种纳米颗粒点阵系统中的磁学和电输运性质有重要的影响.弱偶极相互作用下,系统的磁化强度和隧穿磁电阻随温度的增加而减小.在给定温度时,偶极相互作用强度的增加,使系统出现由低电阻状态向高电阻状态的转变.强偶极相互作用使系统出现明显的磁电阻各向异性.The dot array containing highly densed nanosized magnetic particles has unique magnetic and magnetotransport properties.The magnetism and the tunneling magnetoresistance in the 2D dot array with uniaxial single-domain particles are studied.The nanosized magnetic particles are embedded in an insulating host.The magnetotransport in the dot array comes mainly from the magnetic tunneling mechanism.The orientations of the magnetic particles are directly related to the tunneling magnetoresistance.We found that the strength of the dipolar interaction and the temperature play important roles in the magnetism and magnetoresistance of such dot arrays.At weak dipolar interaction,the magnetism and the tunneling magnetoresistance decrease with the increase of temperature.For a given temperature,the increase of the strength of the dipolar interaction make the system appear a transition from a low resistance state to a high resistance state.At strong dipolar interaction,the system shows a clear anisotropy magnetoresistance.

关 键 词：偶极相互作用 隧穿磁电阻 颗粒点阵 

分 类 号：O241.6[理学—计算数学]