Crystal structures and magnetic properties of zircon-type compounds Lu1-xYxCrO4

We prepared solid solutions of antiferromagnetic LuCrO4 and ferromagnetic LuCrO4, i.e., Lu1-xYxCrO4 (x = 0-1.0 at 0.125 intervals). Their precise crystal structures were determined from the X-ray diffraction measurements. All the solid solutions have a zircon-type structure with space group I4(1)/amd (No. 141). Their magnetic susceptibility measurements have been performed in the temperature range between 1.8 K and 300 K. The solid solutions for x = 0-0.375 show an antiferromagnetic transition and those for x = 0.5-1.0 show a ferromagnetic transition at low temperatures. It was found that the magnetic transition temperatures for the solid solutions were lower than those for pure LuCrO4 (9.1 K) and YCrO4 (9.2 K), and the Curie temperature for Lu0.5Y0.5CrO4 is the lowest (5.2 K). The magnetization curves indicate the occurrence of metamagnetism for Lu0.75Y0.25CrO4 and Lu0.625Y0.375CrO4. Specific heat measurements have been performed for Lu1-xYxCrO4 (x = 0, 0.375, 0.5, 1) in the temperature range between 1.8 K and 300 K. lambda-Type anomalies have been found at their magnetic transition temperatures. Magnetic entropy change due to magnetic exchange interactions has been evaluated from the specific data.