Long-range superexchange in Cu(2)A(2)O(7) (A = P, As, V) as a key element of the microscopic magnetic model

Article

关键词: ANTIFERROMAGNETISM;    MONOPOLES;   

DOI  :  10.1103/PhysRevB.83.094435

来源: SCIE

【 摘 要 】

A microscopic magnetic model for alpha-Cu2P2O7 is evaluated in a combined theoretical and experimental study. Despite a dominant intradimer coupling J(1), sizable interdimer couplings enforce long-range magnetic ordering at T-N = 27 K. The spin model for a-Cu2P2O7 is compared to the models of the isostructural beta-Cu2V2O7 and alpha-Cu2As2O7 systems. As a surprise, coupled dimers in a-Cu2P2O7 and alternating chains in alpha-Cu2As2O7 contrast with a honeycomb lattice in beta-Cu2V2O7. We find that the qualitative difference in the coupling regime of these isostructural compounds is governed by the nature of AO(4) side groups: d elements (A = V) hybridize with nearby O atoms forming a Cu-O-A-O-Cu superexchange path, while for p elements (A = P, As) the superexchange is realized via O-O edges of the tetrahedron. Implications for a broad range of systems are discussed.

【 授权许可】

Free