Peculiarities of pseudogap in Y0.95Pr0.05Ba2Cu3O7−δ single crystals under pressure up to 1.7 GPa

Abstract

The effect of hydrostatic pressure up to P = 1.7 GPa on the fluctuation conductivity σ′(T) and pseudogap ∆*(T) in Y0.95Pr0.05Ba2Cu3O7−δ single crystal with critical temperature Тс = 85.2 K (at P = 0) was investigated. The application of pressure leads to the increase in Tc with dTc/dP = +1.82 K∙GPa−1 while the resistance decreases as dlnρ(100 K)/dP = −(10.5 ± 0.2) %∙GPa−1. Regardless of the pressure, in the temperature interval from Tc to T0 (~88 K at P = 0) the behaviour of σ′(T) is well described by the Aslamazov – Larkin (AL – 3D) fluctuation theory, and above the T0 by the Lawrence – Doniach theory (LD). The Maki-Thompson (MT – 2D) fluctuation contribution is not observed. This indicates the presence of structural defects in the sample induced by Pr. Here it is determined for the first time that when the pressure is applied to the Y1−xPrxBa2Cu3O7−δ single crystal, the pseudogap increases as dlnΔ*/dP = 0.17 GPa–1.

Composition variation and electron irradiation effects on the fluctuation conductivity in Y1–zPrzBa2Cu3O7−δ single crystals

“…In this regard, compounds with a partial substitution of Y for Pr are especially interesting as they allow one to partially suppress superconductivity while keeping the lattice parameters and the oxygen index almost unaltered. In particular, investigations of the effect of Pr impurities on the fluctuation conductivity [23] in such compounds not only contribute to the clarification of the nature of high-temperature superconductivity, but are also relevant for the elaboration of empirical ways to improve the critical parameters of high-T c superconductors.…”

Pressure effect on the electrical resistance of Y0.77Pr0.23Ba2Cu3O7-δ single crystals

“…The use of high hydrostatic pressures continues to be one of the most popular techniques for studying the structural and magnetoresistive characteristics of hightemperature superconducting cuprates (HTSC) [1,2]. Despite the fact that almost 35 years have passed since the discovery of high-temperature superconductors in 1986 by Bednorz and Müller [3], the microscopic mechanism of this unique physical phenomenon still remains unclear.…”

“…Importantly, a significant part of the experimental data was obtained on ceramic, film and textured samples of very different technological background [4,13,15]. In our previous studies [2,16], we investigated the effect of pressure on the resistive characteristics of low-doped praseodymium (х≈0.05) single-crystal samples Y1-xPrxBa2Cu3O7-δ. It was determined that, in contrast to stoichiometric YBa2Cu3O7-δ samples, the application of high pressure to Y0.95Pr0.05Ba2Cu3O7-δ single crystals leads to a double increase in the value of dTc/dP [2,16].…”

“…In our previous studies [2,16], we investigated the effect of pressure on the resistive characteristics of low-doped praseodymium (х≈0.05) single-crystal samples Y1-xPrxBa2Cu3O7-δ. It was determined that, in contrast to stoichiometric YBa2Cu3O7-δ samples, the application of high pressure to Y0.95Pr0.05Ba2Cu3O7-δ single crystals leads to a double increase in the value of dTc/dP [2,16]. In these studies possible mechanisms of the effect of high pressure on Tc, taking into account the presence of features in the electronic spectrum of the carriers were considered [2,16].…”

“…It was determined that, in contrast to stoichiometric YBa2Cu3O7-δ samples, the application of high pressure to Y0.95Pr0.05Ba2Cu3O7-δ single crystals leads to a double increase in the value of dTc/dP [2,16]. In these studies possible mechanisms of the effect of high pressure on Tc, taking into account the presence of features in the electronic spectrum of the carriers were considered [2,16]. In the present study we investigate the effect of hydrostatic pressure on the electrical resistivity in the basal plane of Y1-xPrxBa2Cu3O7-δ single crystals with an average (х≈0.23) concentration of praseodymium and a critical temperature Tc≈67 K. Figure 1 shows the temperature dependences of the electrical resistivity in the basal plane, ρab(T), of the Y1-…”