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TT: Fachverband Tiefe Temperaturen
TT 65: Frustrated Magnets: General I
TT 65.7: Talk
Thursday, March 21, 2024, 11:00–11:15, H 2053
Specific heat of azurite up into the 1/3 magnetization plateau phase — •Carolin Kastner1, Ralf Feyerherm2, and Stefan Süllow1 — 1IPKM, TU Braunschweig, Germany — 2HZB, Berlin, Germany
One dimensional frustrated quantum spin systems are a focus of extensive research efforts due to their exotic magnetic properties at low temperatures. The natural mineral azurite Cu3(CO3)2(OH)2 is one such material, reported as a model compound of the distorted diamond chain. In this system, the Cu2+ ions carry spin-1/2 moments that form monomers and dimers arranged as chains along the crystallographic b axis. An extended 1/3 magnetization plateau was observed to arise at around 11 T when the monomers are fully polarized.
We have investigated the specific heat of azurite up to 14 T to gain insight into the thermodynamic properties in the plateau phase. Below the magnetization plateau, the material exhibits long-range magnetic order, with the specific heat exhibiting a magnon gap behaviour Cmag∝exp−Δm/T. In the plateau phase, also a gap-like behaviour Cmag∝exp−Δp/T is present. The parameters Δm,Δp seemingly disappear at the suppression of antiferromagnetic order of the monomer spins, possibly reflecting quantum critical behaviour.
Keywords: frustrated magnet; quantum magnet; diamond chain; magnetization plateau; specific heat