Thermal expansion coefficients of LaFe11.7Si1.3

The thermal expansion coefficients of LaFe11.7Si1.3 from 85 to 413 K are studied. The volume expands significantly at the Curie temperature 188 K when it changes from the paramagnetic to the ferromagnetic state. The crystallographic structures at 85 and 298 K were determined, and no evidence of a structural transition was found. The thermal expansion coefficients are near constants when the temperature is about 40 K higher or lower than the Curie temperature. From 85 to 143 K, the thermal expansion coefficient is about 3.61(+/-0.26) x 10(-6) K-1, and from 233 to 413 K, it is about 1.17(+/-0.04) x 10(-5) K-1. From 153 to 213 K, the negative nonlinear expansion coefficients are related to the metallic magnetism.