Commensurate structural modulation in the charge- and orbitally-ordered phase of the quadruple perovskite (NaMn${}_3$)Mn${}_4$O${}_{12}$

Abstract

By means of synchrotron x-ray and electron diffraction, we studied the structural changes at the charge order transition $T_{CO}$=176 K in the mixed-valence quadruple perovskite (NaMn${}_3$)Mn${}_4$O${}_{12}$. Below $T_{CO}$ we find satellite peaks indicating a commensurate structural modulation with the same propagation vector q =(1/2,0,-1/2) of the CE magnetic order that appears at low temperature, similarly to the case of simple perovskites like La${}_{0.5}$Ca${}_{0.5}$MnO${}_3$. In the present case, the modulated structure together with the observation of a large entropy change at $T_{CO}$ gives evidence of a rare case of full Mn${}^{3+}$/Mn${}^{4+}$ charge and orbital order consistent with the Goodenough-Kanamori model.

Accepted for publication in Phys. Rev. B Rapid Communications

References in corpus (8)

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Cited by in corpus (6)

• Orbital effects in solids: basics, recent progress and opportunities
• Modulated spin helicity stabilized by incommensurate orbital density waves in a quadruple perovskite manganite
• Striping of orbital-order with charge-disorder in optimally doped manganites
• Universal magneto-orbital ordering in the divalent $A$-site quadruple perovskite manganites $A$Mn${}_7$O${}_{12}$ ($A$ = Ca, Sr, Cd, and Pb)
• Evolution of magneto-orbital order upon B-site electron doping in Na1-xCaxMn7O12 quadruple perovskite manganites
• Direct observation of Jahn-Teller critical dynamics at a charge-order Verwey transition