Nature of the spin dynamics and 1/3 magnetization plateau in azurite.
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=6.5 K.
Rule
K C
KC
Hahn-Meitner-Institut GmbH, D-14109 Berlin, Germany.
Wolter
A U B
AU
Süllow
S
S
Tennant
D A
DA
Brühl
A
A
Köhler
S
S
Wolf
B
B
Lang
M
M
Schreuer
J
J