標題: Possibility of vortex lattice structural phase transition in the superconducting pnictide Ba(Fe0.925Co0.075)(2)As-2
作者: Kopeliansky, R.
Shaulov, A.
Shapiro, B. Ya.
Yeshurun, Y.
Rosenstein, B.
Tu, J. J.
Li, L. J.
Cao, G. H.
Xu, Z. A.
電子物理學系
Department of Electrophysics
公開日期: 1-Mar-2010
摘要: We present magnetic measurements in a single crystal of the newly discovered superconducting ironpnictide Ba(Fe0.925Co0.075)(2)As-2. The magnetization loops exhibit a second magnetization peak (SMP) similar to that observed in most high-temperature superconductors (HTSs). Magnetic relaxation measurements reveal a minimum in the normalized relaxation rate, S = d ln M/d ln t, located in between the SMP onset and the peak fields. The SMP in HTSs is commonly associated with the vortex order-disorder phase transition. However, in Ba(Fe0.925Co0.075)(2)As-2 the onset and peak fields, as well as the minimum point in S, exhibit strong temperature dependence down to low temperatures, excluding the possibility for such a transition. We suggest that the SMP in Ba(Fe0.925Co0.075)(2)As-2 is associated with a vortex structural phase transition from rhombic to square lattice taking place at field and temperatures corresponding to the minimum point of S. A theoretical fit to the transition line, based on a recent theoretical model for vortex structural phase transition, shows good agreement with the experimental results.
URI: http://dx.doi.org/10.1103/PhysRevB.81.092504
http://hdl.handle.net/11536/149917
ISSN: 1098-0121
DOI: 10.1103/PhysRevB.81.092504
期刊: PHYSICAL REVIEW B
Volume: 81
Issue: 9
起始頁: 0
結束頁: 0
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