Dy(Fe_(0-8)Al_(0-2))_2单晶体的宏观量子效应  

MACROSCOPIC QUANTUM EFFECTS IN SINGLE CRYSTAL Dy(Fe_(0-8)Al_(0-2))_2

作　　者：钟文定[1] 陈海英[1] 刘尊孝[1] 吴建华[1] 李国忠[1] 

机构地区：[1]北京大学物理系,北京100871

出　　处：《物理学报》1999年第S1期204-210,共7页Acta Physica Sinica

基　　金：国家自然科学基金!( 批准号:19674002)

摘　　要：测量了Ｄｙ（Ｆｅ０－８Ａｌ０－２）２ 单晶体在［１００］ ，［１１０］ 和［１１１］ 方向上的退磁曲线、内禀矫顽力和磁黏滞性系数随温度的变化．认为退磁曲线出现台阶和大跳跃、内禀矫顽力随温度变化存在峰值、磁黏滞性系数与温度无关等都是畴壁隧穿能垒的宏观量子效应的反映．实验上得出由经典热激活到量子隧穿的交界温度约为５－５ Ｋ．The temperature dependence of demagnetization curve, intrinsic coercivity and magnetic viscosity has been measured on single crystal Dy(Fe 0 8 Al 0 2 ) 2 in \,\ and \ directions. The staircase and a large jump of demagnetization curve, an obvious peak of coercivity vs temperature, and the magnetic viscosity being independent of the temperature etc., were observed. The observed features were analyzed within the theory of the macroscopic quantum effects for domain walls tunneling in the single crystal. A crossover temperature has been observed at T cr =5.5 K between classical thermal activation and quantum tunneling regimes.

关 键 词：磁性宏观量子效应 单晶体 磁黏滞性 反磁化机理 退磁曲线 量子隧穿 热激活 内禀矫顽力 宏观量子现象 畴壁 

分 类 号：O73[理学—晶体学]