【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．更多还原

【Abstract】 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.更多还原