On preparation of nanocrystalline chromites by co-precipitation and autocombustion methods

•ACr2O4 nanopowders, A=Cu, Fe, Ni, Mn and Mg were obtained in high yield.•Co-precipitation and autocombustion routes were optimized for single-phase product.•The nanopowders were examined by X-ray diffraction and vibrational spectroscopy.•Formation of cubic or tetragonal phase in Jahn–Teller NiCr2O4 can be controlled.