Dresden 2020 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Cooperative Phenomena and Phase Transitions (joint session MA/TT)
TT 6.5: Vortrag
Montag, 16. März 2020, 10:30–10:45, HSZ 401
Pressure and field tuning in low-dimensional metal-organic magnets — •Matthew Coak1, Samuel Curley1, David Graf2, Jamie Manson3, and Paul Goddard1 — 1University of Warwick, Coventry, United Kingdom — 2National High Magnetic Field Laboratory, Tallahassee, FL, USA — 3Eastern Washington University, Cheney, WA, USA
The 1D molecular magnet Cu(pyz)(gly)ClO4 (gly = glycine, pyz = pyrazine) is an S = 1/2 dimer material with small enough exchange constants to address with accessible fields. The dimers are coupled antiferromagnetically, possessing a singlet-triplet energy-gap that can be closed upon application of an external magnetic field. When the Zeeman splitting of the degenerate triplet state initially closes the gap, the system passes through a quantum phase transition from a quantum-disordered ground state to a long-range XY-ordered phase. This excited triplet state can be described as a system of bosonic quasi-particles called ‘triplons’. Under certain conditions, this triplon excited state maps onto a Bose-Einstein condensate of magnons; Cu(pyz)(gly)ClO4, at ambient pressures, appears to conform to this picture.
We present our latest results in using hydrostatic pressure as a tuning parameter to control the inter- and intra-dimer exchange interactions and observing the effects on the temperature-field phase diagram.