Neutron diffraction studies of nuclear and magnetic structures in the S=1/2 square Heisenberg antiferromagnets (d{sub 6}-5CAP){sub 2}CuX{sub 4} (X=Br and Cl)

Journal Article · Thu Mar 01 00:00:00 EST 2007 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.75.094424· OSTI ID:20976725

Coomer, F C; Bondah-Jagalu, V; Grant, K J; Harrison, A; McIntyre, G J; Roennow, H M; Feyerherm, R; Wand, T; Meissner, M; Visser, D; McMorrow, D F ^[1]

---

1. Department of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ (United Kingdom)

We report the neutron scattering studies of the nuclear and magnetic structures of deuterated samples of the model two-dimensional S=1/2 Heisenberg antiferromagnets on a square lattice (d{sub 6}-5CAP){sub 2}CuCl{sub 4} and (d{sub 6}-5CAP){sub 2}CuBr{sub 4} (where 5CAP is 2-amino-5-chloropyridinium). Interest in these materials stems from the fact that they have relatively weak exchange between the magnetic ions, and it is therefore possible to perturb their magnetic structures and excitations significantly in experimentally accessible magnetic fields, and thereby access new quantum disordered states. We succeeded in growing fully deuterated single crystals and determined the nuclear and magnetic structures of the bromide at 10 and 1.8 K, respectively, confirming the four-sublattice spin structure expected for systems, where both inter- and intraplane exchange interactions are antiferromagnetic. The determination of the full crystal structure of the bromide highlights the possibility that interlayer exchange may also propagate via hydrogen bonds to and through the 5CAP molecule. We also determined the critical exponents for the sublattice magnetization of the bromide and mapped out the H-T phase diagram of the chloride up to 5 T.

• OSTI ID: 20976725
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 75, Issue 9; Other Information: DOI: 10.1103/PhysRevB.75.094424; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETIC MATERIALS
ANTIFERROMAGNETISM
BROMIDES
CHLORIDES
EXCHANGE INTERACTIONS
EXCITATION
EXCITED STATES
HEISENBERG MODEL
HYDROGEN
MAGNETIC FIELDS
MAGNETIZATION
MONOCRYSTALS
NEUTRON DIFFRACTION
ORGANIC COMPOUNDS
PHASE DIAGRAMS
SPIN
TETRAGONAL LATTICES
TWO-DIMENSIONAL CALCULATIONS