Magnetic Behaviour of the $B{i}_{2-y}S{r}_{y}I{r}_2{O}_7$ Pyrochlore Solid Solution

The temperature dependence of magnetic susceptibility of the Bi${}_{2-y}$Sr${}_y$Ir${}_2$O${}_7$ system was studied from 2 to 300 K. According to these measurements, the solid solution $(0\le y\le 0.9)$ does not show any magnetic transition; however, a noticeable deviation from the Curie-Weiss law occurs and the magnetic behavior of this system can be ascribed to short-range magnetic order that is also present in several geometrically frustrated systems. The Pauli magnetic susceptibility decreases as the Sr content increases, this can be associated with a shift towards Ir${}^{5+}$ in samples; also the Ir effective magnetic moment decreases. The estimated Wilson-ratio indicates the presence of strong electron-electron correlations.