Influence of electronic structure parameters on the electrical transport and magnetic properties of $Y_{2-x}B{i}_{x}I{r}_2{O}_7$ pyrochlore iridates

Abstract

We report the systematic study of structural, magnetic and electrical transport properties of $Y_{2-x}B{i}_{x}I{r}_2{O}_7$ (x = 0.0, 0.1, 0.2, 0.3) pyrochlore iridates. The chemical doping enhances electrical conductivity and antiferromagnetic correlation substantially. The replacement of non-magnetic $Y^{3+}$ ion with non-magnetic $B{i}^{3+}$ in $Y_{2}I{r}_2{O}_7$ tends to reduce the octahedral distortion thus enhancing the antiferromagnetic correlation. Raman spectroscopy shows that the $Ir-O$ bond contract slightly and the $R-O^{\prime }$ bond turn longer as disorder and phononic oscillation are reduced with $Bi$ doping, leading to wider $t_{2g}$ bands, which enhances the electrical conductivity. Additionally, the enhancement in electrical conductivity and antiferromagnetic correlation with $B{i}^{3+}$ doping is attributed to the hybridization between the $Y^{3+}(4p)$/$B{i}^{3+}(6s/6p)$ orbital with $I{r}^{4+}(5d)$ orbital as a result of enhancement in $Ir-O-Ir$ bond angle and contraction in $Ir-O$ bond length.