Nature of the Spin Dynamics and 1/3 Magnetization Plateau in Azurite
Abstract
We present a specific heat and inelastic neutron scattering study in magnetic fields up into the 1/3 magnetization plateau phase of the diamond chain compound azurite Cu3(CO3)2(OH)2. We establish that the magnetization plateau is a dimer-monomer state, i.e., consisting of a chain of S=1/2 monomers, which are separated by S=0 dimers on the diamond chain backbone. The effective spin couplings Jmono/kB=10.1(2)K and Jdimer/kB=1.8(1)K are derived from the monomer and dimer dispersions. They are associated to microscopic couplings J1/kB=1(2)K, J2/kB=55(5)K and a ferromagnetic J3/kB=-20(5)K, possibly as result of dz2 orbitals in the Cu-O bonds providing superexchange (SE) pathways with JSE=6.5K.
- Publication:
-
Physical Review Letters
- Pub Date:
- March 2008
- DOI:
- 10.1103/PhysRevLett.100.117202
- arXiv:
- arXiv:0709.2560
- Bibcode:
- 2008PhRvL.100k7202R
- Keywords:
-
- 75.30.Et;
- 75.10.Pq;
- 75.45.+j;
- Exchange and superexchange interactions;
- Spin chain models;
- Macroscopic quantum phenomena in magnetic systems;
- Condensed Matter - Statistical Mechanics
- E-Print:
- 5 pages, 4 figures