Field-dependent antiferromagnetism and ferromagnetism of the two copper sublattices in Sr{sub 2}Cu{sub 3}O{sub 4}Cl{sub 2}
- Center of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
- School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)
- Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)
- Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)
The Cu{sub 3}O{sub 4} layer in Sr{sub 2}Cu{sub 3}O{sub 4}Cl{sub 2} is a variant of the square CuO{sub 2} lattice of the high-temperature superconductors, in which the center of every second plaquette contains an extra Cu{sup 2+} ion. The ions that make up the conventional CuO{sub 2} network, called CuI, have CuI-CuI exchange energy {approx}130thinspmeV, and order antiferromagnetically at about 380 K; the CuII-CuII exchange is only {approx}10thinspmeV, and the CuII{close_quote}s order at {approx}40thinspK. A study is reported here of the dependence of the magnetization on field, temperature, and crystallographic orientation for this interesting system. We show that the small permanent ferromagnetic moment, that appears when the CuI spins order, and the unusual spin rotation transitions seen most clearly for one particular direction of the magnetic field, are the result of several small bond-dependent anisotropic terms in the spin Hamiltonian that are revealed because of the frustration of the isotropic Heisenberg interaction between CuI and CuII spins. These include a term which favors collinearity of the CuI and CuII spins, which originates from quantum fluctuations, and also the pseudodipolar interaction. Some of these small interactions also come into play in other lamellar cuprates, connected with the high-T{sub c} superconductivity materials, and in many spin-chain and spin-ladder compounds. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 345427
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 59, Issue 22; Other Information: PBD: Jun 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Single-ion anisotropy, crystal-field effects, spin reorientation transitions, and spin waves in R{sub 2}CuO{sub 4} (R=Nd, Pr, and Sm)
Neel transition and sublattice magnetization of pure and doped La sub 2 CuO sub 4