Related papers: Striking Zn impurity effect on the Fe-based superc…
We have performed systematic resistivity and inelastic neutron scattering measurements on Fe$_{0.98-z}$Ni$_z$Te$_{0.5}$Se$_{0.5}$ samples to study the impact of Ni substitution on the transport properties and the low-energy ($\le$ 12 meV)…
Application of pressures or electron-doping through Co substitution into Fe sites transforms the itinerant antiferromagnet BaFe(2)As(2) into a superconductor with the Tc exceeding 20K. We carried out systematic transport measurements of…
We described the effect of nonmagnetic impurity on the superconductivity behavior of the NdFeAsO0.8F0.2 iron-based superconductor. The resistivity measurement showed that the superconductivity suppressed upon increasing the low amounts of…
We investigated systemically YBa2Cu3-x(Fe, Co, Al, Zn)xO7-{\delta} (x=0.0\sim0.5) cuprates through the XRD, the test of superconductivity, oxygen contents,positron annihilation technology and simulated calculations. The experimental results…
We investigate Mn substitution at the Fe site in PrFe1-xMnxAsO0.7F0.3 (0 to 0.1) using structural, Raman, density functional theory (DFT), transport, and magnetic measurements. X-ray diffraction and Raman analyses confirm preferential Mn…
We report on the effect of substitution for Cu on Tc of electron-doped infinite-layer superconductors Sr0.9La0.1Cu1-xRxO2, R = Zn and Ni. We found that Tc was nearly constant until x = 0.03 for R = Zn, while superconductivity was nearly…
We present a systematic study of the impurity effect on Tc in Fe-based superconductors, assuming that the sign-reversal s-wave state due to inter-pocket repulsion ($s_\pm$-wave state) is realized. For this purpose, we introduce several…
We report specific heat measurements on the Fe-based superconductor BaFe2(As0.7P0.3)2, a material on which previous penetration depth, NMR, and thermal conductivity measurements have observed a high density of low-energy excitations, which…
Resistivity, Hall effect, magnetoresistance and DC magnetization were measured in Mn and Zn doped Ba$_{0.5}$K$_{0.5}$Fe$_{2}$As$_{2}$ samples. It is found that the Mn-doping can depress the superconducting transition temperature drastically…
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…
Magnetic properties of $M_{c}$Ta$_{2}$S$_{2}$C ($M$ = Fe, Co, Ni, Cu) have been studied using SQUID DC and AC magnetic susceptibility. In these systems magnetic $M^{2+}$ ions are intercalated into van der Waals gaps between adjacent S…
NMR measurements have been performed on single crystals of Ba$_{1-x}$K$_{x}$Fe$_2$As$_2$ (x = 0, 0.45) and CaFe$_2$As$_2$ grown from Sn flux. The Ba-based pnictide crystals contain significant amounts of Sn in their structure, $\sim 1$%,…
We consider the effect of non-magnetic impurities in a $d_{x^2 - y^2}$ superconductor with $\ef$ close to a van Hove singularity. It is shown that the non-trivial density of states (DOS) allows for resonant scattering already at…
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…
Although their crystal structures are complex, all high temperature superconductors contain some crystal planes consisting of only Cu and O atoms in a square lattice. Superconductivity is believed to originate from strongly interacting…
It is noteworthy that chemical substitution of BaFe2As2 (122) with the noble elements Cu and Au gives superconductivity with a maximum Tc=3 K, while Ag substitution (Ag-122) stays antiferromagnetic. For Ba(Fe1-xTMx)2As2, TM= Cu, Au, or Ag,…
We study the effects of Cu substitution in Fe1.1Te, the non-superconducting parent compound of the iron-based superconductor, Fe1+yTe1-xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions,…
The investigation of Zn substitution in MgB2 polycrystalline samples shows that about 0.1 Zn can be substituted in the structure of Mg deficient samples while it can not be substituted in stoichiometric MgB2. As a result of the isovalent Zn…
BaFe$_2$S$_3$ is a quasi-one-dimensional antiferromagnetic insulator that becomes superconducting under hydrostatic pressure. The magnetic ordering temperature, $T_N$, as well as the presence of superconductivity have been found to be…
We report electronic Raman scattering measurements on optimally doped YBa2Cu3O7 where Zn or Ni impurities have been substituted by Cu. Using Raman selection rules, we have probed the superconducting gap in the nodal and antinodal regions.…