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Front Cover: A‐site magnetism in A‐site‐ordered perovskite‐structure oxides. Status Solidi B 3/2012)
Author(s) -
Shimakawa Yuichi,
Saito Takashi
Publication year - 2012
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201290003
Subject(s) - front cover , cover (algebra) , magnetism , perovskite (structure) , front (military) , materials science , geology , condensed matter physics , crystallography , physics , chemistry , engineering , mechanical engineering , oceanography
The A‐site‐ordered perovskite‐structure oxides AA′ 3 B 4 O 12 are attracting much interest due to their large variety of physical properties. When the B‐site ions in AA′ 3 B 4 O 12 are nonmagnetic species, one can see very unusual magnetic behaviors of spins in the A‐ and A′‐site sublattices. In their Feature Article on pp. 423–434 , Shimakawa and Saito summarize the A‐site magnetism in the A‐site‐ordered perovskite‐structure oxides. The authors synthesized some new compounds under high‐pressure and high‐temperature conditions. They found that either ferromagnetism (CaCu 3 Ge 4 O 12 and CaCu 3 Sn 4 O 12 ) or antiferromagnetism (CaCu 3 Ti 4 O 12 ) arises in the cubic A′‐site Cu 2+ ( S = 1/2) spin sublattice. The ferromagnetic Cu‐Cu direct‐exchange interaction and the antiferromagnetic Cu‐O‐Ti‐O‐Cu superexchange interaction are mutually competitive, and a perfect balance of the interactions in a solid‐solution sample causes unusual instability. The cover picture shows ferromagnetic and antiferromagnetic spin structures of the A‐site‐ordered perovskite‐structure oxides and the changes of magnetic susceptibility and inverse susceptibility for the solid solutions.