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Structural, vibrational, thermal, and magnetic properties of mullite‐type NdMnTiO 5 ceramic
Author(s) -
Ghosh Kowsik,
Murshed M. Mangir,
Frederichs Thomas,
Muniraju Naveen K. C.,
Gesing Thorsten M.
Publication year - 2022
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.18261
Subject(s) - paramagnetism , neutron diffraction , orthorhombic crystal system , antiferromagnetism , magnetic susceptibility , crystallography , rietveld refinement , materials science , raman spectroscopy , magnetic moment , crystal structure , chemistry , nuclear magnetic resonance , condensed matter physics , physics , optics
Mullite‐type R Mn 2 O 5 ( R = Y, rare‐earth element) ceramics are of ongoing research attention because of their interesting crystal‐chemical and magnetic properties. We report nuclear and magnetic structures of NdMnTiO 5 together with its spectroscopic, thermogravimetric, and magnetic properties. The polycrystalline sample is prepared by solid‐state synthesis and characterized from neutron and X‐ray powder diffraction data Rietveld refinements. NdMnTiO 5 crystallizes in the orthorhombic space group Pbam with metric parameter a = 755.20(1) pm, b = 869.91(1) pm, c = 582.42(1) pm, and V = 382.62(1) 10 6 pm 3 . The Mn 3+ and Ti 4+ cations are observed to be located in the octahedral and pyramidal sites, respectively. The vibrational features in these polyhedral sites are characterized by Raman and Fourier transform infrared spectroscopes. The higher decomposition temperature of NdMnTiO 5 , compared to other R Mn 2 O 5 phases, is explained in terms of the higher bond strength of Ti‐O bonds than those of Mn‐O bonds. Temperature‐dependent DC magnetic susceptibility suggests a paramagnetic to antiferromagnetic phase transition at 43(1) K. Inverse susceptibility in the paramagnetic region above 120 K follows the Curie‐Weiss law, resulting in a magnetic moment of 6.33(1) μ B per formula unit. Neutron diffraction data collected at 7.5 K reveal that the magnetic moments of Nd 3+ and Mn 3+ in NdMnTiO 5 are incommensurately ordered with a propagation vector k = (0, 0.238, 0.117).