Magnetic inhomogeneities in the quadruple perovskite manganite [Y${}_{2-x}$Mn${}_x$]MnMnMn${}_4$O${}_{12}$

Abstract

A combination of competing exchange interactions and substitutional disorder gives rise to magnetic inhomogeneities in the [Y${}_{2-x}$Mn${}_x$]MnMnMn${}_4$O${}_{12}$ $x=0.23$ and $x=0.16$ quadruple perovskite manganites. Our neutron powder scattering measurements show that both the $x=0.23$ and $x=0.16$ samples separate into two distinct magnetic phases; below T${}_1$ = 120 $\pm$ 10 K the system undergoes a transition from a paramagnetic phase to a phase characterised by short range antiferromagnetic clusters contained in a paramagnetic matrix, and below T${}_2$ $\sim$ 65 K, the system is composed of well correlated long range collinear ferrimagnetic order, punctuated by short range antiferromagnetic clusters. A sharp increase in the antiferromagnetic phase fraction is observed below $\sim$ 33 K, concomitant with a decrease in the ferrimagnetic phase fraction. Our results demonstrate that the theoretically proposed AFM phase is stabilised in the [Y${}_{2-x}$Mn${}_x$]MnMnMn${}_4$O${}_{12}$ manganites in the presence of dominant B-B exchange interactions, as predicted.

12 pages, 6 figures

References in corpus (4)

• Coulomb Interactions and Nanoscale Electronic Inhomogeneities in Manganites
• Spontaneous Rotation of Ferrimagnetism Driven by Antiferromagnetic Spin Canting
• The magnetic structure and spin-flop transition in the A-site columnar-ordered quadruple perovskite $\mathrm{TmM}{\mathrm{n}}_3{\mathrm{O}}_6$
• Unusual effects of magnetic dilution in the ferrimagnetic columnar ordered $\mathrm{S}{\mathrm{m}}_2\mathrm{MnMnM}{\mathrm{n}}_{4-\mathrm{x}}\mathrm{T}{\mathrm{i}}_{\mathrm{x}}{\mathrm{O}}_{12}$ perovskites