Triple A-Site Cation Ordering in the Ferrimagnetic Y2CuGaMn4O12 Perovskite.
Inorg Chem
; 61(36): 14428-14435, 2022 Sep 12.
Article
em En
| MEDLINE
| ID: mdl-36044365
ABSTRACT
A new member of A-site columnar-ordered A2A'Aâ³B4O12 quadruple perovskites with the composition of Y2CuGaMn4O12 was prepared by a high-pressure, high-temperature method at 6 GPa and about 1500 K. Its crystal structure and cation distributions were studied by powder synchrotron X-ray and neutron diffraction. There is a triple A-site cation ordering with some degrees of anti-site disorder among sites occupied by 3d transition metals [Y2]A[Cu0.8Mn0.2]A'[Ga0.8Mn0.2]Aâ³[Mn3.6Cu0.2Ga0.2]BO12. It has the space group P42/nmc (no. 137) between 1.5 and 873 K with a = 7.33884 Å and c = 7.66251 Å at 297 K. Despite anti-site disorder, it exhibits a long-range ferrimagnetic order at TC = 115 K with the ordered moment of 2.19 µB at each B site and 0.89 µB at the A' or Aâ³ site. Magnetic moments are aligned along the c axis; all moments are ordered ferromagnetically at the B sites, and the moments at the A' or Aâ³ site are ordered in the opposite direction. Cu2+ doping drastically changes magnetic properties as "parent" Y2MnGaMn4O12 just shows spin-glass magnetic properties without long-range ordering. Anisotropic thermal expansion was observed in Y2CuGaMn4O12 the lattice parameter a almost linearly decreases from 1.5 K to TC and then monotonically increases up to 873 K (almost linearly from 300 K); the parameter c monotonically increases from 1.5 to 300 K and then decreases up to 600 K.
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MEDLINE
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Ano de publicação:
2022
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Article