Double Double Cation Order in the High‐Pressure Perovskites MnRMnSbO₆

Abstract

Cation ordering in ABO3 perovskites adds to their chemical variety and can lead to properties such as ferrimagnetism and magnetoresistance in Sr2 FeMoO6 . Through high-pressure and high-temperature synthesis, a new type of "double double perovskite" structure has been discovered in the family MnRMnSbO6 (R=La, Pr, Nd, Sm). This tetragonal structure has a 1:1 order of cations on both A and B sites, with A-site Mn(2+) and R(3+) cations ordered in columns and Mn(2+) and Sb(5+) having rock salt order on the B sites. The MnRMnSbO6 double double perovskites are ferrimagnetic at low temperatures with additional spin-reorientation transitions. The ordering direction of ferrimagnetic Mn spins in MnNdMnSbO6 changes from parallel to [001] below TC =76 K to perpendicular below the reorientation transition at 42 K at which Nd moments also order. Smaller rare earths lead to conventional monoclinic double perovskites (MnR)MnSbO6 for Eu and Gd.

Large Magnetoelectric Coupling Near Room Temperature in Synthetic Melanostibite Mn2FeSbO6

“…[10][11][12][13][14] In contrast, type-I multiferroics tend to show much higher ferroic transition temperatures at the expense of as mall MEC. [16][17][18][19][20][21] Herein we report the exceptional case of amassive MEC effect at the elevated temperature of 260 Kon polycrystals of the high pressure ilmenite Mn 2 FeSbO 6 (I_Mn 2 FeSbO 6 ). [16][17][18][19][20][21] Herein we report the exceptional case of amassive MEC effect at the elevated temperature of 260 Kon polycrystals of the high pressure ilmenite Mn 2 FeSbO 6 (I_Mn 2 FeSbO 6 ).…”

Intrinsic Triple Order in A‐site Columnar‐Ordered Quadruple Perovskites: Proof of Concept

“…Among A‐site‐ordered structures, the 1 : 3 body‐centered ordering of AA′ 3 B 4 O 12 quadruple perovskites is dominant ,,. There are possibilities of simultaneous ordering at the A and B sites as in the so‐called doubly ordered (or double double), perovskites AA′BB′O 6 and in AA′ 3 B 2 B′ 2 O 12 quadruple perovskites …”

“…[5] Among A-site-ordered structures, the 1 : 3 body-centered [4] ordering of AA' 3 B 4 O 12 quadruple perovskites is dominant. [4,6,7] There are possibilities of simultaneous ordering at the A and B sites as in the so-called doubly ordered [4] (or double double) [8,9] perovskites AA'BB'O 6 [10] and in AA' 3 B 2 B' 2 O 12 quadruple perovskites. [11] There are four Glazer octahedral tilt systems that result in Asite ordering: a + a + a + (1 : 3), a + a + c À (1 : 1 : 2), a 0 b + b + (1 : 1 : 2) and a 0 b + b À (1 : 1), [4,6] where numbers in parenthesis give the number and ratio among non-equivalent A sites.…”

“…[4,7] The a + a + c À (1 : 1 : 2) tilt system results in the so-called A-site columnar-ordered A 2 A'A''B 4 O 12 quadruple perovskites with a ten-fold coordinated A site, a square-planar coordinated A' site, and a tetrahedrally coordinated A'' site ( Figures 1 and S1). [12] However, in the majority of examples reported so far, A' and A'' cations are the same (A' = A''), and the intrinsic triple order is hidden, for example, in CaFeTi 2 O 6 , [13] CaMnTi 2 O 6 , [14] RMnMnSbO 6 (R = La, Pr, Nd and Sm), [8] RMnGaTiO 6 (R = Sm and Gd), [15] RMnMn 2 O 6 RMn 3 O 6 (R = Gd-Tm and Y), [16] CaMnFeReO 6 [9] and CaMnMnReO 6 , [9] where short formula look like double perovskites. There is only one example where A' and A'' cations are different, Ca 2 CuMnFe 2 Re 2 O 12 , and this compound shows a partial ordering of Cu 2 + and Mn 2 + between the A' and A'' 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 sites.…”

Synthesis, Crystal Structure, and Magnetic Properties of MnFe3O5

“…As M = Fe and Ca phases are already known, it seems likely that an M = Mn analogue should also be accessible at pressure. High pressure is known to stabilize high spin Mn 2+ ion in unusual coordination environments, for example, at the A cation sites of the ABO 3 perovskite structure in MnVO 3 ; double perovskites Mn 2 FeSbO 6 , Mn 2 ScSbO 6 , Mn 2 FeReO 6 ,, and Mn 2 MnReO 6 (Mn 3 ReO 6 ); 134 types ζ‐Mn 2 O 3 and MnCu 3 V 4 O 12 ; and the new “double double” cation ordered phases Mn R MnSbO 6 ( R = La, Pr, Nd, Sm) . We report herein the synthesis and initial characterization of the structure and magnetic properties of MnFe 3 O 5 .…”