3D-xycritical properties of YBa₂Cu₄O₈and magnetic-field-induced 3D to 1D crossover

Abstract

Abstract. We present reversible magnetization data of a YBa 2 Cu 4 O 8 single crystal and analyze the evidence for 3D-xy critical behavior and a magnetic field induced 3D to 1D crossover. Remarkable consistency with these phenomena is observed in agreement with a magnetic field induced finite size effect, whereupon the correlation length transverse to the applied magnetic field cannot grow beyond the limiting magnetic length scale L H = (Φ 0 / (aH)) 1/2 . By applying the appropriate scaling form we obtain the zero-field critical temperature, the 3D to 1D crossover, the vortex melting line and the universal ratios of the related scaling variables. Accordingly there is no continuous phase transition in the (H, T )-plane along the H c2 -lines as predicted by the mean-field treatment.

Evidence for Kosterlitz-Thouless and three-dimensionalXYcritical behavior inBi2Sr2CaCuSchneider1, Giannini2 2009Phys. Rev. B17170View full textAdd to dashboardCite

“…Indeed, in Bi 2 Sr 2 CaCu 2 O 8+δ this peak shifts, 18 opposite to the generic behavior. 4,6 Given the Maxwell relation, vs. T for various magnetic fields reveals consistency with the anomalous shift of the specific heat peak. Indeed the dip shifts towards higher temperatures.…”

“…1,2,3,4,5, 6 It was realized that in these materials the critical regime where thermal fluctuations dominate can be attained and that some of them are in addition quasi two dimensional (2D). 7 Furthermore, the systematics of the superconducting properties uncovered that the anisotropy is further enhanced with underdoping.…”

Magnetic field induced 3D–1D crossover in type-II superconductors

“…Since the magnetic field induced finite size effect relies on thermal fluctuations and there enhancement originating from the 3D to 1D crossover, the observability of the magnetic field induced finite size effect should not be restricted to type-II superconductors with small correlation volume only. In these systems, including YBa 2 Cu 4 O 8 [10], NdBa 2 Cu 3 O 7−δ [11], YBa 2 Cu 3 O 7−δ [12,13], and DyBa 2 Cu 3 O 7−δ [14], 3D-xy critical behavior was observed already in zero field. Indeed, our analysis of the reversible magnetization of RbOs 2 O 6 [15] and the specific heat of Nb 77 Zr 23 [16], Nb 3 Sn [17] and NbSe 2 [18] reveals that even in these low T c superconductors with comparatively large correlation volume the 3D to 1D crossover is observable in sufficiently high magnetic fields.…”

“…Invoking a Maxwell relation we then derive the scaling properties of the magnetization and specific heat near the 3D to 1D crossover line. We are then prepared to analyze the specific heat and reversible magnetization data of YBa 2 Cu 4 O 8 [10], NdBa 2 Cu 3 O 7−δ [11], YBa 2 Cu 3 O 7−δ [12,13], and DyBa 2 Cu 3 O 7−δ [14], where critical fluctuations have been observed already in the zero field transition. Subsequently we analyze the reversible magnetization of RbOs 2 O 6 [15] and the specific heat of Nb 77 Zr 23 [16], Nb 3 Sn [17] and NbSe 2 [18], type-II superconductors with comparatively large correlation volume, to explore the associated enhancement of thermal fluctuations due to the 3D to 1D crossover.…”

“…In Fig. 2 we depicted the scaling plot T H c d 2 m/dT 2 vs. tH −3/4 c of a YBa 2 Cu 4 O 8 single crystal taken from Weyeneth et al [10]. It corresponds to Eq.…”