Magnetic and Crystallographic Properties of LnCrO_4 (Ln=Nd,Sm,and Dy)

摘要

Zircon-type compounds LnCrO_4(Ln=Nd,Sm,and Dy) were prepared.Their precise crystal structures at room temperature were determined from X-ray diffraction measurements.These compounds have a tetragonal system with space group I4_1/amd.Magnetic susceptibility and specific heat measurements have been performed for all the compounds in the temperature range between 1.8 and 300 K.For NdCrO_4,an antiferromagnetic transition was found at 25.2K.SmCrO_4 and DyCrO_4 show magnetic transitions at 15.0 and 22.8K,respectively.In addition,structural phase transitions were observed at 58.5 and 31.2K,respectively.For DyCrO_4,the crystal structure below the transition temperature was determined by low-temperature powder X-ray diffraction measurements to be orthorhombic with space group Imma.