Scaling analysis of the static and dynamic critical exponents in underdoped, overdoped, and optimally dopedPr2−xCexCuO4

Abstract

We report on current-voltage measurements of the zero-field normal-superconducting phase transition in thin films of Pr 2−x Ce x CuO 4−y as a function of doping. We find that the small size of the critical regime in these materials ͑Ϸ25 mK͒ gives rise to mean-field behavior at the phase transition with a static exponent of Ϸ 0.5 for all dopings ͑in contrast to hole-doped YBa 2 Cu 3 O 7−␦ ͒. We also find mean-field behavior in the dynamic exponent z. This indicates that Pr 2−x Ce x CuO 4−y behaves similarly to conventional superconductors in contrast to other cuprate superconductors. However, as the transition width in our samples decreases, the dynamic critical exponent approaches z = 1.5, similar to the critical exponent found in hole-doped YBa 2 Cu 3 O 7−␦ .

Voltage-current properties of superconducting amorphous tungsten nanostrips

“…In the vortex liquid phase for the temperature above T g , the linear resistivity at low current behaves as,The V-I isotherm at T g should satisfy the power law, with . Previous theoretical and experimental studies show that and are reasonable values for a 3D VG phase transition1679. In recent years, quasi-2D VG transitions have been reported, and the ranges of and are similar to those for 3D12.…”

“…In the presence of strong disorder, the zero resistance state corresponds to a vortex glass (VG) phase and with increasing temperature the transition to the vortex liquid phase induces a dissipative state217. This transition has been demonstrated by transport measurement in HTS systems like YBa 2 Cu 3 O 7 (YBCO)13, Pr 2-x Ce x CuO 4-y (PCCO)7 and Bi 2 Sr 2-x La x CuO 6 + δ (BSLCO)46. However, VG transition-like behavior in conventional low critical temperature superconductors (LTS) has only been observed in very few systems, like Nb8910, In11, and Mo 3 Si13 films.…”

“…The existence of vortices in the mixed state of a superconductor is one of the most fascinating research topics in superconducting physics12345678910111213141516. The vortices can form liquid, crystalline, and glassy phases.…”

“…The vortices can form liquid, crystalline, and glassy phases. The discovery of high critical temperature ( T C ) superconductors (HTS) has made the detailed study of vortex phases possible because of the large anisotropy and thermal fluctuations in HTS systems1234567. In the presence of strong disorder, the zero resistance state corresponds to a vortex glass (VG) phase and with increasing temperature the transition to the vortex liquid phase induces a dissipative state217.…”

Vortex-glass transition and vortex pinning behavior in three-dimensional NbTiN epitaxial films

“…transitions in type-II superconductors in the presence of a penetrating magnetic field and proposed the existence of a vortex-glass (VG) phase with zero resistance, which would convert to a dissipative vortex-liquid (VL) phase with increasing temperature [5,6]. Experimentally, the existence of such a transition has been unambiguously observed in some high temperature superconductors and iron-based superconductors with moderate disorder such as YBa 2 Cu 3 O 7 [7,8], Bi 2 Sr 2 Ca 2 Cu 3 O x [9], Tl 2 Ba 2 CaCu 2 O 8 [10], Pr 2−x Ce x CuO 4−y [11], (Ba,K)Fe 2 As 2 [12], FeSe 1−x Te x [13], SmFeAsO 0.85 [14], BaFe 2 As 2 [15], and FeSn [16]. In principle, the scenario of the VG transition is also applicable to the disordered conventional superconductors.…”