Thermal Expansion in Itinerant Electron Magnetic Ni3Al System

Thermal expansion in the itinerant electron magnetic Ni 3 Al system has been measured at temperatures 4.2 K≤ T ≤60 K. In the ferromagnetic samples (74.6, 75.0 and 75.2 at%Ni) in this system, a linear thermal expansion coefficient α shows a jump at the respective T c , and the behavior of α in the temperature region near the respective T c is well explained by the self-consistent renormalization (SCR) theory of spin fluctuations by Moriya and Usami. In the paramagnetic sample (74.0 at%Ni) the behavior of α is also explained by this theory very well. Moreover the inverse magnetic susceptibility, χ -1 in the paramagnet shows the T 4/3 -dependence in the region of high temperatures T ≥13 K and the T 2 -dependence below about 13 K. In the ferromagnets χ -1 shows the T 4/3 -dependence above the respective T c . These facts agree with the prediction by the SCR theory of spin fluctuations.