Double Double Cation Order in the High-Pressure Perovskites MnRMnSbO6.
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.
Dpto. Quimica Inorganica I, Fac. Quimicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
Elena
E
Solana-Madruga
Centre for Science at Extreme Conditions (CSEC) and School of Chemistry, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3JZ, UK.
Ángel M
ÁM
Arévalo-López
Dpto. Ingeniería mecánica, química y diseño industrial, ETSIDI, Universidad Politécnica de Madrid, 28012, Madrid, Spain.
Antonio J
AJ
Dos Santos-García
Centro Nacional de Microscopía Electrónica, Universidad Complutense de Madrid, 28040, Madrid, Spain.
Esteban
E
Urones-Garrote
Dpto. Quimica Inorganica I, Fac. Quimicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
David
D
Ávila-Brande
Dpto. Quimica Inorganica I, Fac. Quimicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
Regino
R
Sáez-Puche
Centre for Science at Extreme Conditions (CSEC) and School of Chemistry, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3JZ, UK. j.p.attfield@ed.ac.uk.
J Paul
JP
Attfield
double perovskites; high-pressure chemistry; magnetic properties; perovskite phases; solid-state structures