Two different types of fluxes, namely sodium based and chloride based fluxes were used to grow Cr substituted barium and strontium hexaferrite ferrite crystals, (Sr,Ba)Fe 12 À x Cr x O 19 at comparatively low temperatures of about 1300 C. The sodium based flux led to growth of larger crystals up to 5 mm, but with only minor Cr contents x 0.07. From the chloride based flux the obtained Cr contents are significantly higher with x ¼ 5.7 (Sr) and x ¼ 3.4 (Ba), however, crystals reach only sizes in the sub-mm range. X-ray absorption spectroscopy data support exclusively isovalent substitution of Fe 3þ by Cr 3þ even for very low Cr contents. 57 Fe M€ oßbauer spectroscopy reveals Cr to preferentially occupy the six-fold by oxygen coordinated site at 12k and, to a lower degree, 2a and 4f 2 in space group P6 3 /mmc. All characteristic magnetic properties drop upon Cr substitution, e. g., the Curie temperature from 728 K for pure BaFe 12 O 19 to 465 K for BaFe 8.6 Cr 3.4 O 19 , the saturation magnetization from 71 emu/g to 29.7 emu/g and the coercive field from 363 Oe to 45 Oe.