MnFe 0.5 Ru 0.5 O 3 : An above-room-temperature antiferromagnetic semiconductor

Document Type

Article

Publication Date

1-1-2019

Abstract

A transition-metal-only MnFe 0.5 Ru 0.5 O 3 polycrystalline oxide was prepared by a reaction of starting materials MnO, MnO 2 , Fe 2 O 3 , RuO 2 at 6 GPa and 1873 K for 30 minutes. A combination of X-ray and neutron powder diffraction refinements indicated that MnFe 0.5 Ru 0.5 O 3 adopts the corundum (α-Fe 2 O 3 ) structure type with space group R3c, in which all metal ions are disordered. The centrosymmetric nature of the MnFe 0.5 Ru 0.5 O 3 structure is corroborated by transmission electron microscopy, lack of optical second harmonic generation, X-ray absorption near edge spectroscopy, and Mössbauer spectroscopy. X-ray absorption near edge spectroscopy of MnFe 0.5 Ru 0.5 O 3 showed the oxidation states of Mn, Fe, and Ru to be 2+/3+, 3+, and ∼4+, respectively. Resistivity measurements revealed that MnFe 0.5 Ru 0.5 O 3 is a semiconductor. Magnetic measurements and magnetic structure refinements indicated that MnFe 0.5 Ru 0.5 O 3 orders antiferromagnetically around 400 K, with magnetic moments slightly canted away from the c axis. 57 Fe Mössbauer confirmed the magnetic ordering and Fe 3+ (S = 5/2) magnetic hyperfine splitting. First principles calculations are provided to understand the electronic structure more thoroughly. A comparison of synthesis and properties of MnFe 0.5 Ru 0.5 O 3 and related corundum Mn 2 BB′O 6 derivatives is discussed.

Identifier

85060169463 (Scopus)

Publication Title

Journal of Materials Chemistry C

External Full Text Location

https://doi.org/10.1039/c8tc05059g

e-ISSN

20507526

ISSN

20507534

First Page

509

Last Page

522

Issue

3

Volume

7

Grant

DMR-1420620

Fund Ref

U.S. Department of Energy

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