Pervin Rukshana, Krishnan Manikanadan, Rana Amit Kumar, Kannan M, Arumugam S, Shirage Parasharam M
Discipline of Metallurgy Engineering and Materials Science & Physics, Indian Institute of Technology Indore, Simrol Campus, Khandwa road, Indore 453552, India.
Phys Chem Chem Phys. 2017 May 10;19(18):11230-11238. doi: 10.1039/c7cp00784a.
Magnetization measurements have been used to determine the effect of magnetic impurities (Fe) on the Larkin-Ovchinnikov (LO) 3D collective pinning model in NbSe single crystals. Upon increasing the concentration of Fe impurities, the superconducting critical current density enhances appreciably compared to pure NbSe reflecting the fact that the addition of magnetic impurities assists in improving the practical applicability of NbSe. The random pinning potential that is introduced by the Fe impurities also shows a considerable change in the interaction between the vortices and the core region, resulting in a competitive nature of single vortex, small bundle and large bundle pinning regimes in the H-T phase diagram. The intrinsic disorder in pure NbSe single crystals shows δT flux pinning; however, the extrinsic disorder created by Fe atoms in NbSe shows δl flux pinning. Furthermore, the field dependence of the pinning force on both NbSe and Fe-incorporated NbSe represents the existence of point pinning and the surface pinning mechanism with a broadening of the f curves in the Fe-incorporated single crystals.
磁化测量已被用于确定磁性杂质（铁）对NbSe单晶中Larkin-Ovchinnikov（LO）三维集体钉扎模型的影响。随着铁杂质浓度的增加，与纯NbSe相比，超导临界电流密度显著提高，这反映出添加磁性杂质有助于提高NbSe的实际适用性。铁杂质引入的随机钉扎势也表明，涡旋与核心区域之间的相互作用发生了相当大的变化，导致在H-T相图中出现单涡旋、小束和大束钉扎机制的竞争特性。纯NbSe单晶中的固有无序表现为δT磁通钉扎；然而，NbSe中由铁原子产生的外在无序表现为δl磁通钉扎。此外，NbSe和掺铁NbSe上钉扎力的场依赖性均表明存在点钉扎和表面钉扎机制，且掺铁单晶中的f曲线变宽。
