Low-temperature coefficient of resistivity in LaFe13-xSix compounds

The resistivity of metal materials usually increases as the temperature rises and the temperature coefficient of resistivity (TCR) could be a few thousand (ppm/K). In fact, this would cause trouble to the accurate measuring instrument used in varying temperature conditions. Thus, it is a great challenge to develop materials with a low-temperature coefficient of resistivity (L-TCR). In this paper, we synthesized LaFe13-xSix compounds showing LTCR behavior. The X-ray powder diffraction (XRD) patterns revealed that the crystal structure of LaFe13-xSix compounds changes from a cubic structure to a tetragonal structure as the Si component rises, and new phases like LaSi2 and FeSi appear. By testing electrical property, we find that the local extremum of the TCR is obtained in LaFe5Al8 compound, which is -54.4 ppm/K over 5-300 K.