Room-temperature zero thermal expansion in a cubic perovskite oxide SrCu₃Fe_4−xMn_xO₁₂

A zero thermal expansion in a wide temperature range including room temperature has been achieved in a cubic perovskite oxide SrCu₃Fe_4−xMn_xO₁₂ for x = 1.5. Partial substitution of Mn for Fe in SrCu₃Fe₄O₁₂ systematically changes the linear thermal expansion coefficient from negative [−6.4(2), −5.7(5), and −1.88(11) ppm/K for x = 0.5, 1, and 1.25, respectively] to almost zero [0.67(15) ppm/K for x = 1.5] to positive [2.97(17) ppm/K for x = 1.75] and the operational temperature window shifts to higher temperature ranges above room temperature. Crystal structure analysis and Mössbauer spectroscopy reveal that the zero thermal expansion for x = 1.5 composition is induced by intermetallic charge transfer between Cu and (Fe,Mn) ions. These results display the high potential of SrCu₃Fe_4−xMn_xO₁₂ for the development of zero thermal expansion materials.