Cooling rate dependence of nanostructures of spinel-type manganese oxide ZnMnGaO4

Abstract Cooling rate dependence of the nanostructures of spinel-type manganese oxide ZnMnGaO4 was studied via transmission electron microscopy (with selected area electron diffraction and bright- and dark-field imaging) as well as X-ray diffraction. The Quench sample exhibited a tweed pattern, suggesting the coexistence of two phases at the nanometer scale. The nanostructural changes from a fine twin structure to a checkerboard nanostructure, followed by the emergence of a lamellar-type nanostructure, were clearly observed as the cooling rate decreased from quenching to 1 °C/h. It was suggested that the diffusion of manganese ions accompanied by the Jahn–Teller distortion play an important role in the formation of nanostructures of this system.