Torque magnetometry on single-crystal high-temperature superconductors near the critical temperature: A scaling approach

J. Hofer; T. Schneider; J. M. Singer; M. Willemin; H. Keller; T. Sasagawa; K. Kishio; K. Conder; J. Karpinski

doi:10.1103/PhysRevB.62.631

← Back to search

Torque magnetometry on single-crystal high-temperature superconductors near the critical temperature: A scaling approach

J. Hofer, T. Schneider, J. M. Singer, M. Willemin, H. Keller, T. Sasagawa, K. Kishio, K. Conder, J. Karpinski

DOI 10.1103/PhysRevB.62.631 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

Angular-dependent magnetic torque measurements performed near the critical temperature on single crystals of HgBa2CuO4+y, La2−xSrxCuO4, and YBa2Cu3O6.93 are scaled, following the three-dimensional (3D) XY model, in order to determine the scaling function dG±(z)/dz which describes the universal critical properties of high-Tc cuprates near Tc. A systematic shift of the scaling function with increasing effective mass anisotropy γ=mc*/ma* is observed, which may be understood in terms of a 3D-2D crossover. Further evidence for a 3D-2D crossover is found from temperature-dependent torque measurements carried out in different magnetic fields at different field orientations δ, which show a quasi-2D crossing region (M*,T*). The occurrence of this crossing phenomenon is explained in a phenomenological way from the weak z dependence of the scaling function around a value z=z*. The crossing temperature T* is found to be angular dependent. Torque measurements above Tc reveal that fluctuations are strongly enhanced in the underdoped regime where the anisotropy is large, whereas they are less important in the overdoped regime.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
HgBa2CuO4+y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
YBa2Cu3O6.93 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Bi2.15Sr1.85CaCu2O8+y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
La1.914Sr0.086CuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
HgBa2CuO4.096 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	100.46	Pressure not reported	unknown
HgBa2CuO4.108 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
La1.854Sr0.146CuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	33.68	Pressure not reported	unknown
La1.920Sr0.080CuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown