Magnetic behavior of the Bi2−ySryIr2O7 pyrochlore solid solution

The temperature dependence of magnetic susceptibility of the Bi2−ySryIr2O7 system was studied from 2 to 300 K. According to these measurements, the solid solution (0≤y≤0.9)(0≤y≤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 Ir5+ in samples; also the Ir effective magnetic moment decreases. The estimated Wilson-ratio indicates the presence of strong electron–electron correlations.

Graphical abstractTemperature dependence of the magnetic susceptibility of Bi2−ySryIr2O7. The samples of this system showed no magnetic transition down to 2 K. Analyzing magnetic data (symbols for experimental data, continuous line for the Curie–Weiss (CW) equation and black dots for a modified CW equation), it is found that this system departures from a CW-like equation and the magnetic parameters C and θθ notably deviate from the expected values for Ir. Better fittings with a modified CW equation are shown in the A and B insets.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The magnetic susceptibility of the Bi2−xSrxIr2O7 system is discussed. ► No magnetic transition is observed. ► Magnetic measurements on the Bi2−ySryIr2O7 indicate the existence of Ir5+. ► The magnetic susceptibility does not follow a Curie–Weiss law. ► A modified Curie–Weiss equation describes correctly the magnetic susceptibility.