Intrinsic pinning on structural domains in underdoped single crystals of Ba(Fe1-xCox)(2)As-2

TitleIntrinsic pinning on structural domains in underdoped single crystals of Ba(Fe1-xCox)(2)As-2
Publication TypeJournal Article
Year of Publication2009
AuthorsProzorov R, Tanatar MA, Ni N, Kreyssig A, Nandi S, Bud'ko SL, Goldman AI, Canfield PC
Journal TitlePhysical Review B
Date Published11/01
ISBN Number1098-0121
Accession NumberISI:000272310400088
Keywordsbarium compounds, cobalt compounds, critical current density (superconductivity), doping, flux pinning, iron compounds, magnetic anisotropy, magnetic domain walls, phase diagrams, superconducting, superconducting critical field, superconducting materials

Critical current density was studied in single crystals of Ba(Fe1-xCox)(2)As-2 for the values of x spanning the entire doping phase diagram. A noticeable enhancement was found for slightly underdoped crystals with the peak at x=0.058. Using a combination of polarized-light imaging, x-ray diffraction and magnetic measurements we associate this behavior with the intrinsic pinning on structural domains in the orthorhombic phase. Domain walls extend throughout the sample thickness in the direction of vortices and act as extended pinning centers. With the increasing x domain structure becomes more intertwined and fine due to a decrease in the orthorhombic distortion. This results in the energy landscape with mazelike spatial modulations favorable for pinning. This finding shows that iron-based pnictide superconductors, characterized by high values of the transition temperature, high upper critical fields, and low anisotropy may intrinsically have relatively high critical current densities.

URL<Go to ISI>://000272310400088