Thermal Expansion Anomaly of Tb₂Fe₁₄Cr₃ Compound

We investigate the thermal expansion property of the Tb₂Fe₁₄Cr₃ compound by means of x-ray diffraction. The result shows that the Tb₂Fe₁₄Cr₃ compound has a hexagonal Th₂Ni₁₇-type structure. Negative thermal
expansion is found in the Tb₂Fe₁₄Cr₃ compound from 296 to 493K by x-ray dilatometry. The coefficient of the average thermal expansion is α=-2.82 × 10^-5K^-1. In the temperature range 493--692K, the coefficient of the average thermal expansion is α=1.59 × 10^-5K^-1. The physical mechanism of thermal expansion anomaly of the Tb₂Fe₁₄Cr₃ compound is discussed according to the temperature dependence of magnetization measured by a superconducting quantum interference device.