La2MnVO6 double perovskite: a structural, magnetic and X-ray absorption investigation

Tapas Kumar Mandal; Mark Croft; Joke Hadermann; Gustaaf Van Tendeloo; Peter W. Stephens; Martha Greenblatt

doi:10.1039/B823513A

La₂MnVO₆ double perovskite: a structural, magnetic and X-ray absorption investigation†

Tapas Kumar Mandal,^a Mark Croft,^b Joke Hadermann,^c Gustaaf Van Tendeloo,^c Peter W. Stephens^d and Martha Greenblatt*^a

Author affiliations

* Corresponding authors

^a Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ, USA
E-mail: martha@rutchem.rutgers.edu
Fax: +1 732 445 5312

^b Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ, USA

^c Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp, Belgium

^d Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, USA

Abstract

The synthesis, electron diffraction (ED), synchrotron X-ray and neutron structure, X-ray absorption spectroscopy (XAS) and magnetic property studies of La₂MnVO₆ double perovskite are described. Analysis of the synchrotron powder X-ray diffraction data for La₂MnVO₆ indicates a disordered arrangement of Mn and V at the B-site of the perovskite structure. Absence of super-lattice reflections in the ED patterns for La₂MnVO₆ supports the disordered cation arrangement. Room temperature time-of-flight (TOF) neutron powder diffraction (NPD) data show no evidence of cation ordering, in corroboration with the ED and synchrotron studies (orthorhombic Pnma, a = 5.6097(3), b = 7.8837(5) and c = 5.5668(3) Å; 295 K, NPD). A comparison of XAS analyses of La₂TVO₆ with T = Ni and Co shows T²⁺ formal oxidation state while the T = Mn material evidences a Mn³⁺ admixture into a dominantly Mn²⁺ ground state. V-K edge measurements manifest a mirror image behavior with a V⁴⁺ state for T = Ni and Co with a V³⁺ admixture arising in the T = Mn material. The magnetic susceptibility data for La₂MnVO₆ show ferromagnetic correlations; the observed effective moment, µ_eff (5.72 µ_B) is much smaller than the calculated moment (6.16 µ_B) based on the spin-only formula for Mn²⁺ (d⁵, HS) /V⁴⁺ (d¹), supportive of the partly oxidized Mn and reduced V scenario (Mn³⁺/V³⁺).

This article is part of the themed collection: Dedicated to Professor C. N. R. Rao

Article information

https://doi.org/10.1039/B823513A

Article type

Paper

Submitted

06 Jan 2009

Accepted

25 Mar 2009

First published

24 Apr 2009

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J. Mater. Chem., 2009,19, 4382-4390

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La₂MnVO₆ double perovskite: a structural, magnetic and X-ray absorption investigation

T. K. Mandal, M. Croft, J. Hadermann, G. Van Tendeloo, P. W. Stephens and M. Greenblatt, J. Mater. Chem., 2009, 19, 4382 DOI: 10.1039/B823513A

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Journal of Materials Chemistry