تغییرحجم یاخته بسیط بدون تغییر فاز بلوری و پیدایش اثر کوندو در نقطه بحرانی ترکیبات بین فلزی بر پایه عنصر مغناطیسی Gd

In this paper, results from X-ray diffraction and the variation of electric resistance versus temperature of Gd3AuxAl1-x intermetallic compound are reported. All samples formed in orthorhombic crystalline structure with Pnma space group. In measuring the lattice parameters by X-ray diffraction method, deviation from Vegard’s rule has been seen. This deviation at x = 0.4 maximizes. In addition, an abrupt volume change equal to 6% occurs at the critical point x = 0.4. For all samples, by increasing the x-parameter, we have seen increasing in the Curie temperature Tc. Magnetic susceptibility χ(T) is increased versus x-parameter, too. The results of electric resistance measuring in sample with critical value (x = 0.4) shows a behavior like Kondo effect which is not observed in other samples. For compounds based on Gd, this undesirable behavior could be related to 4f sublevel which it concentrates free electrons around Gd ion.