Dutta Surajit, Roy Indranil, Basistha Somak, Mandal Soumyajit, Jesudasan John, Bagwe Vivas, Raychaudhuri Pratap
Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005, India.
J Phys Condens Matter. 2020 Feb 13;32(7):075601. doi: 10.1088/1361-648X/ab52b8. Epub 2019 Oct 30.
We investigate the magnetic field variation of the thermally activated flux flow resistivity, ρ and flux flow critical current density, J , in a weakly pinned thin film of the amorphous superconductor a-MoGe, where vortices are in a fluid state over a large range of magnetic fields. We show that both quantities can be understood within the framework of collective pinning theory. In particular, our results demonstrate that a 'peak effect' can arise at the order-disorder transition of the vortex lattice even when both the ordered and disordered states are vortex fluids, such as the boundary between a hexatic vortex fluid and an isotropic vortex liquid.
我们研究了非晶态超导体α-MoGe弱钉扎薄膜中热激活磁通流电阻率ρ和磁通流临界电流密度J的磁场变化，在该薄膜中，涡旋在大范围磁场中处于流体状态。我们表明，这两个量都可以在集体钉扎理论的框架内得到理解。特别是，我们的结果表明，即使有序态和无序态都是涡旋流体，如六方涡旋流体和各向同性涡旋液体之间的边界，在涡旋晶格的有序-无序转变处也可能出现“峰值效应”。
