Related papers: Effects of transition metal doping in MgB$_2$ supe…
We investigate the currently debated issue concerning whether transition metal substitutions dope carriers in iron based superconductors. From first-principles calculations of the configuration-averaged spectral function of BaFe$_2$As$_2$…
Effects of magnetic impurity on the superconductivity has been investigated in Mg1-xMnB2. With increase of Mn concentration x, the lattice constant c (perpendicular to the boron sheet) decreases at a rate of -1.4 % (= dlnc/dx), while a…
Magnetic ions (Mn) were substituted in MgB_2 single crystals resulting in a strong pair-breaking effect. The superconducting transition temperature, T_c, in Mg_{1-x}Mn_xB_2 has been found to be rapidly suppressed at an initial rate of 10…
We study theoretically the current debatable issue about the effect of transition-metal (TM) substitution in iron-based superconductors through treating all of the TM ions as randomly distributed impurities. The extra electrons from TM…
Density functional calculations are used to investigate the effects of partial substitutional alloying of the B site in MgB2 with C and Be alone and combined with alloying of the Mg site with Cu. The effect of such substitutions on the…
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…
We investigated the doping effects of magnetic and nonmagnetic impurities on the single-crystalline p-type Ba0.5K0.5Fe2-2xM2xAs2 (M = Mn, Ru, Co, Ni, Cu and Zn) superconductors. The superconductivity indicates robustly against impurity of…
Topological insulators are characterized by the existence of band inversion and the possibility of the realization of surface states. Doping with a magnetic atom, which is a source of the time-reversal symmetry breaking, can lead to…
We examined doping effect of 3d transition metal elements (TM: Cr, Mn, Co, Ni, and Cu) at the Fe site of a quaternary fluoroarsenide CaFeAsF, an analogue of 1111-type parent compound LaFeAsO. The anomaly at ~120 K observed in resistivity…
We have investigated the effect of transition metal dopants on the local structure of the prototypical 0.75 Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$-0.25 PbTiO$_3$ relaxor ferroelectric. We find that these dopants give rise to very different local…
We have studied the changes in the electronic structure and the superconducting transition temperature T_c of Mg(B_{1-x}C_{x})_{2} alloys as a function of x with 0\leq x\leq 0.3. Our density-functional-based approach uses coherent-potential…
Superconducting transition temperatures ($T_c$'s) of MgB$_2$, Mg$_{1-x}$Ca$_x$B$_2$, Mg$_{1-x}$Na$_x$B$_2$, and Mg$_{1-x}$Al$_x$B$_2$ are studied within the McMillan approximation using electronic and structural information obtained from…
Taking cue from the increase in the superconducting transition temperature (Tc) of Fe1+xSe via nominal (2 wt%) substitution of Cr instead of excess Fe, we have now extended our study with nominal substitution (<=5 wt%) with other transition…
The discovery of superconductivity in copper oxide compounds has attracted considerable attention over the past three decades. The high transition temperature in these compounds, exhibiting proximity to an antiferromagnetic order in their…
Mg2NiH4 is a promising hydrogen storage material with fast (de)hydrogenation kinetics. Its hydrogen desorption enthalpy, however, is too large for practical applications. In this paper we study the effects of transition metal doping by…
Structure, transport and magnetic properties have been investigated for layered NaCo1-xMnxO2 materials. With the increase of Mn-doping amount, measurements of x-ray diffraction indicate that the in-plane lattice parameter a decreases…
We have investigated the effect of Ti doping on the transport properties coupled with the magnetic ones in Sm$_{0.55}$Sr$_{0.45}$Mn$_{1-\eta}$Ti$_{\eta}$O$_3$ ($0 \leq \eta \leq 0.04$). The parent compound, Sm$_{0.55}$Sr$_{0.45}$MnO$_3$,…
The $ab$-plane resistivity and Hall effect are studied in Fe$_{1-y}$M$_y$Te$_{0.65}$Se$_{0.35}$ single crystals doped with two transition metal elements, M = Co or Ni, over a wide doping range, $0 \leq y \leq 0.2$. The superconducting…
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…
The effects of substituting nonmagnetic Mg2+ and Zn2+ ions for the Mn2+ (S = 5/2) ions on the structural, magnetic and dielectric properties of the multiferroic frustrated antiferromagnet MnWO4 were investigated. Polycrystalline samples of…