Behavior In Whole Temperature Range Research Articles

Evolution of magnetic and transport properties in hole doped Y2Ir2O7

We report the effect of Ru4+ substitution at Ir-site on structural, magnetic and electrical properties in pyrochlore iridate Y2Ir2O7. Structural investigation has been done using x-ray powder diffraction and Rietveld analysis for both samples. There is no structural phase transition with Ru doping. Magnetization study shows that on slightly substitution of Ru at Ir-site effectively shifts the magnetic irreversible temperature Tirr towards low temperature and reduce the bifurcation between MZFC and MFC branches. The electrical resistivity shows an insulating behavior in whole temperature range, however, resistivity decreases with doping of Ru.

Evolution of structure, magnetism, and electronic transport in the doped pyrochlore iridate Y2Ir2−xRuxO7

The interplay between spin-orbit coupling (SOC) and electron correlation ($U$) is considered for many exotic phenomena in iridium oxides. We have investigated the evolution of structural, magnetic and electronic properties in pyrochlore iridate Y$_2$Ir$_{2-x}$Ru$_{x}$O$_7$ where the substitution of Ru has been aimed to tune this interplay. The Ru substitution does not introduce any structural phase transition, however, we do observe an evolution of lattice parameters with the doping level $x$. X-ray photoemission spectroscopy (XPS) study indicates Ru adopts charge state of Ru$^{4+}$ and replaces the Ir$^{4+}$ accordingly. Magnetization data reveal both the onset of magnetic irreversibility and the magnetic moment decreases with progressive substitution of Ru. These materials show non-equilibrium low temperature magnetic state as revealed by magnetic relaxation data. Interestingly, we find magnetic relaxation rate increases with substitution of Ru. The electrical resistivity shows an insulating behavior in whole temperature range, however, resistivity decreases with substitution of Ru. Nature of electronic conduction has been found to follow power-law behavior for all the materials.

Studies on a possible superconducting system Y [sbnd]Cu [sbnd]Se

Two new phases have been discovered. in a possible superconducting system Y Cu Se. One is a tetragonal phase with a=b=3.875Å, c= 8.687Å. Another is a hexagonal phase with a=b= 4.03Å,c=6.58Å. Both phases exhibit metallic conduction behavior from 300K to 4.2K. The tetragonal phase shows antimagnetic property from 300K to 68K but paramagnetic property below 68K. While the hexagonal phase possesses paramagnetic behavior in whole temperature range. The samples with partial replacement of Y by Sr or Ba, show antiferromagnetic transition.