Synthesis and Magnetic Characterization of Double Perovskites

Geometric magnetic frustration occurs when magnetic ions are arranged spatially such that magnetic order is inhibited. Frustrated materials are of interest to the research community due to their rich magnetic phase diagrams, exhibiting exotic physics and sensitivity to parameters such as doping and structural distortion. We have performed SQUID susceptibility measurements on the following 4$d^{\mathrm{1}}$/5$d^{\mathrm{1}}$ (Mo$^{\mathrm{5+}}$/W$^{\mathrm{5+}})$ double perovskite compounds: Ba$_{\mathrm{2}}$YbMoO$_{\mathrm{6}}$, Ba$_{\mathrm{2}}$LuWO$_{\mathrm{6}}$, Ba$_{\mathrm{2}}$YWO$_{\mathrm{6}}$, Ba$_{\mathrm{2}}$ScMoO$_{\mathrm{6}}$, and Sr$_{\mathrm{2}}$ScMoO$_{\mathrm{6}}$. Double perovskites exhibit frustration in the presence of antiferromagnetic correlations. In our measurements, all five compounds exhibited Curie-Weiss behavior with large and negative Curie-Weiss temperatures indicative of antiferromagnetic correlations. No evidence of magnetic order was found to 2K, indicating high frustration indices as seen in spin-singlet candidates such as Ba$_{\mathrm{2}}$YMoO$_{\mathrm{6}}$ and Ba$_{\mathrm{2}}$LuMoO$_{\mathrm{6}}$.