Mn2FeSbO6: A ferrimagnetic ilmenite and an antiferromagnetic perovskite

Abstract

Due of its polymorphism, Mn2FeSbO6 can be synthesized at high pressures and temperatures as a ferrimagnetic ilmenite or an antiferromagnetic perovskite. The structural phase transformation is discussed in detail, and magnetic structures are proposed for both phases. The high-pressure Mn2FeSbO6 polymorph is a rare example of A2B B O6 perovskite with solely Mn cations on the A-site. Fe and Sb cations are ordered on the B-sites. Theoretical calculations for the perovskite phase suggest a complex magnetic structure, holding an electronic polarization. MFSO cannot be synthesized under ambient pressure. Yet it was shown that MFSO ilmenite could be synthesized with relatively high purity using thermobaric treatments [6,7]. MFSO ilmenite was found to order ferrimagnetically below 270 K. By increasing the pressure employed during the thermobaric synthesis, a double perovskite phase of MFSO may be stabilized, with Mn cations on the A-site, and Fe, Sb cations ordered on the B-site.We show in the present article that the perovskite phase has magnetic properties quite different from those of the ilmenite one, namely is antiferromagnetic below 60 K. We discuss the phase transformation from ilmenite to perovskite in MFSO based on X-ray powder diffraction results. Using theoretical calculations, we predict a complex magnetic structure, and electronic polarization of the perovskite phase.Mn 2 FeSbO 6 ilmenite, i.e. with the same structure as the mineral material, was synthesized as ceramic using the following thermobaric treatment: pressure P = 3 GPa, temperature T = 1000 o C, duration d = 30 mins (see Ref. [6,7] for details). By increasing the pressure to 6 GPa (and duration to 40 mins), a perovskite phase of MFSO could be stabilized [7]. Crystal structure and stoichiometry of ilmenite and perovskite MFSO were investigated by X-ray powder diffraction (XRPD) on a D8 Bruker diffractometer using CuK α1 radiation and microprobe energy-dispersive spectroscopy analysis. Magnetization and heat capacity measurements were performed using a superconducting quantum interference device (SQUID) MPMS magnetometer and PPMS physical property measurement system from Quantum Design Inc. Complementary high-temperature magnetization measurements were performed using the VSM/oven option of the PPMS. Electronic structure calculations were performed to predict the magnetic ordering of the perovskite phase. Crystal and some of the magnetic structures were drawn using VESTA [8].arXiv:1210.4368v2 [cond-mat.str-el]

Mn2FeWO6: A New Ni3TeO6‐Type Polar and Magnetic Oxide

“…The A 2 BB′O 6 ‐type corundum derivatives can crystallize in the centrosymmetric ilmenite (IL, space group R ‐3), or in non‐centrosymmetric LiNbO 3 (LN, R 3 c ), or ordered ilmenite (OIL, R 3), or Ni 3 TeO 6 (NTO, R 3) structure, as shown in Figure S1 (Supporting Information). The stabilization of any one of these structures depends on the cation arrangement and their ordering/disordering degree, which are affected by the cationic size and charge differences, electron configuration, and synthesis conditions . The general structural features of A 2 BB′O 6 ‐type corundum derivatives with octahedral coordination of all metal sites favor the formation of practical magnetic and multiferroic/magnetoelectric materials by incorporation of magnetic transition metal ions.…”

Low‐Temperature Cationic Rearrangement in a Bulk Metal Oxide

“…Cationic rearrangements below 300 °C have only been reported in nanocrystals, or when driven by applied external electrical potential as in battery materials, but not in bulk metal oxides by temperature alone. The corundum‐derived A 2 BB′O 6 family of compounds can incorporate transition metal ions at all of the cationic sites and adopt different cation order–disorder configurations, providing an ideal platform for materials engineering . Recently, the polar room‐temperature ( T C ≈337 K) ferrimagnet Mn 2 FeMoO 6 , hereafter called phase I, was prepared by quenching to room temperature from 1350 °C at a pressure of 8 GPa .…”

“…The corundum-derived A 2 BB'O 6 family of compounds can incorporate transition metal ions at all of the cationic sites and adopt different cation order-disorder configurations, providing an ideal platform for materials engineering. [5,8,9,[17][18][19][20][21][22] Recently, the polar roomtemperature (T C % 337 K) ferrimagnet Mn 2 FeMoO 6 , hereafter called phase I, was prepared by quenching to room temperature from 1350 8C at a pressure of 8 GPa. [21] Firstprinciples calculations indicated that the band gap, the magnetic and electronic properties, and the ground-state energy of Mn 2 FeMoO 6 are governed by the arrangement of cations in the unit cell, which suggested effective property control through cationic arrangement.…”

Structural and magnetic properties of nickel antimony ferrospinels

“…Sample 2 contained a minute impurity phase of the binary oxide NiSb 2 O 6 , whereas sample 1 was found to be a pure, single phase spinel without impurity phases. One original motivation for this study was to prepare and study the Ni based synthetic analog of the natural mineral melanostibite, Mn 2 FeSbO 6 , which crystallizes in the structural type ilmenite [16]. However, the ilmenite Ni 2 FeSbO 6 did not form in this preparation method.…”