Research of solid solution on the basis of GaSb of an alloys of Yb_xGa_1–xSb (0≤ x ≤0.05) system has been carried out at temperature Т = 300 K, and also in a wide temperature interval (100–1000 К). For definition of the mechanism of dispersion of the carrier of a current Nerns–Ettengshanzen effect is measured in this sample. Weak magnetic fields  are defined from the formula . If  r <1 or r >1 it can be assumed that dispersion of a current carrier from alloyed ions take place at temperature (200–250) K  and at more high temperature (~550 K) at dispersion – from lattice  thermal fluctuations.