Magnetic order near 270 K in mineral and synthetic Mn2FeSbO6 ilmenite

Abstract

The structural and magnetic properties of Mn 2 FeSbO 6 single-crystalline mineral and ceramic samples synthesized under thermobaric treatment have been investigated, and compared to theoretical predictions based on first-principles electronic structure calculations. This ilmenite system displays a sharp magnetic transition just below the room temperature related to a ferrimagnetic ordering of the Mn 2+ and Fe 3+ cations, which makes Mn 2 FeSbO 6 a promising candidate for designing functional magnetic materials.

Mn2FeSbO6: A ferrimagnetic ilmenite and an antiferromagnetic perovskite

“…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.…”

“…Figure 3 (upper panels) shows the temperature T dependence of the magnetization M (plotted as M/H) for both MFSO compounds. While the ilmenite compound displays a ferrimagnetic transition near 270 K [6], perovskite MFSO (lower panel) exhibits a paramagnetic response near that temperature. On the other hand a peak is observed in the magnetization curves near 60 K, suggesting antiferromagnetic ordering below that temperature.…”

“…Magnetic hysteresis measurements performed at low temperatures (T = 10 K, not shown) indicate a linear response to magnetic field in perovskite MFSO, in contrast to the ilmenite case. [6] The inverse susceptibility of the perovskite material does not exactly follow a Curie-Weiss behavior above 100 K; however considering a near-linear behavior of H/M data measured at higher temperatures (300 K < T < 500K, not shown) yields a Curie-Weiss temperature θ CW ∼ -180 K. The respective magnetic transitions of the two MFSO materials are also observed in the heat capacity C curves depicted in Fig. 3, at 268 K and 59 K respectively.…”

“…Mn 2 FeSbO 6 (MFSO) ilmenite-type mineral, called melanostibite [6], contains two magnetic ions (Mn 2+ and Fe 3+ ) on different crystallographic sites. MFSO cannot be synthesized under ambient pressure.…”

“…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].…”