磁通交流响应的锁模特性研究  

MODE-LOCKING BEHAVIOR IN THE AC RESPONSE OF VORTEX LATTICE

作　　者：曹义刚[1] 焦正宽[1] 

机构地区：[1]浙江大学物理系,杭州310027

出　　处：《低温物理学报》2003年第4期287-290,共4页Low Temperature Physical Letters

摘　　要：本文数值研究无序磁通点阵的交流响应 .我们在交流驱动力叠加的速度 直流驱动力曲线上发现了锁模台阶 .台阶宽度随交流驱动力振幅呈Bessel函数振荡 .台阶速度线性依赖于交流驱动力频率 .此外 ,我们还首次考察了温度对锁模特性的影响 .发现 :台阶速度不随温度的变化而改变 ,直至台阶消失 ;热涨落将抹平钉扎势 ,因此破坏微观速度的调制 ,另外热涨落还破坏磁通的相干运动 。We investigate numerically the ac response of 2D disordered vortex lattice. In the presence of a superimposed ac force, a mode locking step is observed in the velocity direct current (dc) force characteristics at high dc forces. The step width shows Bessel function like oscillations with the ac force amplitude. The step velocity depends linearly on the ac force frequency. The influence of temperature on the mode locking behavior is examined for the first time. Thermal fluctuations smooth the pinning potential and increase with increasing temperature, thus destroying the microscopically periodic velocity modulation and the coherence of moving vortex lattice. These result in an exponential decrease of the step width with increasing temperature.

关 键 词：无序磁通点阵 超导电性 锁模特性 交流响应 热涨落 交流驱动力 温度 磁通运动 微观速度 台阶速度 

分 类 号：O513[理学—低温物理]