Magnetic order near 270 K in mineral and synthetic Mn$_2$FeSbO$_6$   ilmenite
  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. 
R. Mathieu, S. A. Ivanov, G. V. Bazuev, M. Hudl, P. Lazor, I. V.   Solovyev, P. Nordblad
cond-mat.str-el