Mn$_2$FeSbO$_6$: a ferrimagnetic ilmenite and an antiferromagnetic   perovskite
  Due of its polymorphism, Mn$_2$FeSbO$_6$ 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 Mn$_2$FeSbO$_6$ polymorph is a rare example of $A_2 B'B"$O$_6$ 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. 
R. Mathieu, S. A. Ivanov, I. V. Solovyev, G. V. Bazuev, P. Anil Kumar,   P. Lazor, P. Nordblad
cond-mat.str-el