Related papers: Isotope exponent in disordered underdoped and over…
The effect of disorder on the superconducting transition temperature $T_{c}$ of cuprate superconductors is examined. Disorder is introduced into the cation sites in the plane adjacent to the CuO$_{2}$ planes of two single-layer systems,…
Substitution of isovalent non-magnetic defects, such as Zn, in CuO2 plane strongly modifies the magnetic properties of strongly electron correlated hole doped cuprate superconductors. The reason for enhanced uniform magnetic susceptibility,…
The effect of Zn substitution on the superconducting transition temperature, Tc, was investigated for the La2-xSrxCu1-yZnyO4 (Zn-LSCO) compounds over a wide range of hole concentration, p (= x), and Zn content (y) in the CuO2 plane. Zn…
The effects of non-magnetic iso-valent defects inside the CuO2 plane(s) on superconducting transition temperature, Tc, dc charge transport, and the bulk magnetic susceptibility, \c{hi}(T), were investigated for the YBa2(Cu1-yZny)3O7-d…
The effect of Zn substitution in the CuO2 plane on the superconducting transition temperature, Tc, was studied for the La2-xSrxCu1-yZnyO4 and YBa2(Cu1-yZny)3O7-d compounds over a wide range of hole concentration, p, and Zn content (y). Zn…
We have studied the oxygen-isotope effects on T_{c} and in-plane penetration depth \lambda_{ab}(0) in an optimally doped 3-layer cuprate Bi_{1.6}Pb_{0.4}Sr_{2}Ca_{2}Cu_{3}O_{10+y} (T_{c} \sim 107 K). We find a small oxygen-isotope effect on…
The role of substantial in-plane disorder (Zn) on the transport and AC susceptibility of Y1-xCaxBa2(Cu1-yZny)3O7-delta was investigated over a wide range of planar hole concentration, p. Resistivity, r(T), for a number of overdoped to…
We comment on the paper published by W.B. Gao, Q.Q. Liu, L.X. Yang, Y.Yu, F.Y. Li, C.Q. Jin and S. Uchida in Phys. Rev. B 80, 094523 (2009) and give alternate explanations for the enhanced superconductivity. The enhanced onset Tc of 98K…
We report on a study of the influence of defects introduced in the CuO$_{2}$ planes of cuprates in a wide range of hole dopings n. T$_{c}$ and electrical resistivity $\rho (T)$ measurements have been performed on electron irradiated…
Since the early days of the discovery of hole doped high-Tc cuprates, the variation of the oxygen isotope exponent (IE) with the number of doped holes, p, in the CuO2 planes has been a source of considerable debate. There is a growing…
Using the large-$N$ limit of the $t$-$J$ model and allowing also for phonons and the electron-phonon interaction we study the isotope effect $\alpha$ for coupling constants appropriate for YBCO. We find that $\alpha$ has a minimum at…
The influence of various kinds of impurities on the isotope shift exponent \alpha of high temperature superconductors has been studied. In these materials the dopant impurities, like Sr in La_{2-x}Sr_xCuO_4, play different role and usually…
The planar oxygen isotope effect coefficient measured as a function of hole doping in the Pr- and La-doped YBa2Cu3O7 (YBCO) and the Ni-doped La1.85Sr0.15CuO4 (LSCO) superconductors quantitatively and qualitatively follows the form…
We have carried out measurements of the pressure dependence to 1.2 GPa of the oxygen isotope effect on $T_c$ in the high-$T_c$ superconductor YBa$_2$Cu$_4$O$_8$ using a clamp cell in a SQUID magnetometer. This compound lies close to, but…
The effects of planar hole content, p (= x), on the uniform (q = 0) magnetic susceptibility, c(T), of La2-xSrxCu1-yZnyO4 were investigated over a wide range of Sr (x) and Zn (y) contents. A strongly p-dependent Zn-induced magnetic behavior…
Oxygen doping in metallic YBa_2Cu_3O_x induces quadrupolar "alpha-ortho'', and breathing "beta-ortho" deformations of the CuO_2 planes. Breathing beta-ortho deformations favour hybridizations of the pd sigma Cu3d_x^2-y^2 - O2p_x,y with the…
Our paper on the isotope effect in high-temperature superconductors with cation substitutions presents a comprehensive analysis rooted completely in the experimental evidence. In this Reply we show that pair-breaking disorder, isotope…
In YBa2Cu3Ox, distinct features are found in the pressure dependence of the transition temperature, dTc/dp, and in DeltaCp*Tc, where DeltaCp is the jump in the specific heat at Tc: dTc/dp becomes zero when DeltaCp*Tc is maximal, whereas…
We have measured the effect of oxygen isotope substitution on the ab-plane reflectance of underdoped YBCO. The frequency shift of the transverse optic phonons due to the substitution of O-16 by O-18 yields an isotope effect of the expected…
The effect of non-magnetic Zn impurity on superconductivity in LaFe$_{1-y}$Zn$_y$AsO$_{1-x}$F$_x$ system is studied systematically. In the presence of Zn impurity, the superconducting transition temperature increases in the under-doped…