Hydrostatic-pressure tuning of magnetic, nonmagnetic, and superconducting states in annealed Ca(Fe1-xCox)(2)As-2

TitleHydrostatic-pressure tuning of magnetic, nonmagnetic, and superconducting states in annealed Ca(Fe1-xCox)(2)As-2
Publication TypeJournal Article
Year of Publication2012
AuthorsGati E, Kohler S, Guterding D, Wolf B, Knoner S, Ran S, Bud'ko SL, Canfield PC, Lang M
Journal TitlePhysical Review B
Volume86
Pages220511
Date Published12
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000312832400001
Abstract

We report on measurements of the magnetic susceptibility and electrical resistance under He-gas pressure on single crystals of Ca(Fe1-xCox)(2)As-2. We find that for properly heat-treated crystals with modest Co concentration, x = 0.028, the salient ground states associated with iron-arsenide superconductors, i.e., orthorhombic/antiferromagnetic (o/afm), superconducting, and nonmagnetic collapsed-tetragonal (cT) states can be accessed all in one sample with reasonably small and truly hydrostatic pressure. This is possible owing to the extreme sensitivity of the o/afm (for T <= T-s,T-N) and superconducting (T <= T-c) states against variation of pressure, disclosing pressure coefficients of dT(s,N)/dP = -(1100 +/- 50) K/GPa and dT(c)/dP = -(60 +/- 3) K/GPa, respectively. Systematic investigations of the various phase transitions and ground states via pressure tuning revealed no coexistence of bulk superconductivity (sc) with the o/afm state which we link to the strongly first-order character of the corresponding structural/magnetic transition in this compound. Our results, together with literature results, indicate that preserving fluctuations associated with the o/afm transition to low enough temperatures is vital for sc to form. DOI: 10.1103/PhysRevB.86.220511

URL<Go to ISI>://WOS:000312832400001
DOI10.1103/PhysRevB.86.220511