Ferri- and ferro-magnetism in CaMnMReO₆ double double perovskites of late transition metals M = Co and Ni

Abstract

Doubly ordered perovskites are reported for CaMnMReO6 (M = Co, Ni). CaMnNiReO6 is a remarkable example of a ferromagnetic oxide with four distinct spin sublattices all collinearly ordered below TC = 152 K.

Ferrimagnetism and spin reorientation in the high-pressure double double perovskites CaMnCrSbO6 and CaMnFeSbSolana‐Madruga1, Kearins2, Alharbi3 et al. 2021Phys. Rev. MaterialsSelf Cite

“…Among the nine possible double double (doubly ordered) AA'BB'O6 structures, 2 only those combining rock-salt order of B-site cations with layered 3 , 4 or columnar A cation order have been reported. The latter type was recently reported for MnRMnSbO6 (R = rare earth) 5 , 6 and CaMnBReO6 (B = transition metal) 7,8 compositions. Both systems show a rich variety of magnetic properties.…”

“…The same site preference was observed for Co and Ni in the CaMnBReO6 (B = Co, Ni) analogs. 8 However Cr shows no preference with almost 20% substitution at both Mn sites. 5% B/Sb antisite disorder is observed for B = Cr, but B = Fe is more disordered with 13% inversion.…”

“…The tendency for d 10 Sb 5+ to displace off-center is evidenced by a relatively high octahedral distortion factor Δ in the B = Cr structure, whereas the greater level of antisite disorder for B = Fe leads to a very regular average Sb/FeO6 octahedron with small Δ. Ca sits in the large cuboctahedral void with a 10-fold coordination and all Ca-O distances between 2.36 and 2.80 Å, in good agreement with the typical bond lengths for Ca in other double double perovskites. 7,8,13 Fig. 1.…”

Evolution of cation and spin orders in the double–double-double perovskite series CaxMn2−xFeReO6

“…When half of the Mn 2+ was replaced by Ca 2+ , the product CaMnFeReO6 was found to have an AA'BB´O6 double double perovskite structure with columnar 1:1 A/A'-site order of 10-coordinate Ca 2+ and 4-coordinate Mn 2+ as well as rocksalt 1:1 B/B'-Fe/Re cation order [25]. This tetragonal P42/n double double perovskite structure type is also observed in the RMnMnSbO6 (R = La, Pr, Nd, Sm [26,27]) series as well as in CaMnMReO6 (M = Mn [25], Co and Ni [28]) and Ca(Mn0.5Cu0.5)FeReO6 [25]. These double double perovskites all require high pressure synthesis.…”

Double Double to Double Perovskite Transformations in Quaternary Manganese Oxides

“…A family with A‐site layered and B‐site rock‐salt arrangements, for example, NaLaMgWO 6 [10] and NaYNiWO 6 , [11] is stabilised by the charge difference between large A + and A′ 3+ cations. A second DDPv family with columnar A‐site and rock‐salt B site orders has recently been reported in RMnMnSbO 6 (for rare earths R=La, Pr, Nd and Sm) [12, 13] and several CaMnBB′O 6 materials (B=Mn, Fe, Co, Ni for B′=Re, [14–16] and B/B′=Fe/Ta, [17] Cr/Sb and Fe/Sb [18] ) synthesised at high temperatures and pressures. The A‐site order in this tetragonal P 4 2 / n family is driven by cation size differences between R 3+ or Ca 2+ and Mn 2+ .…”