Abstract Non-destructive local measurements of the spontaneous magnetization M s over a small volume (≈10 -2 mm 3) have been carried out on two Ga-YIG single crystals, prepared under different growth conditions, using the Larmor precession of a neutron beam transmitted through a platelet shaped sample. The first of them was prepared by the classical high temperature solution (HTS) flux method and the second adding the accelerated crucible rotation technique (ACRT), and enhancing the crucible size. The samples were characterized by optical and X-ray topographic means. The results indicate that: a) M s increases along the growth directions for the HTS grown sample; in our special case, two different regions with very distinct rates of increase in M s are clearly in evidence; b) M s is more homogeneous when the ACRT is used; c) M s is constant, within our resolution (3%) for the regions of the sample grown at the same time. The main part of these results is confirmed by performing a direct measurement of the magnetization of small cubes cut out from the adjacent slice of the as-grown crystals.