Berlin 2008 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 2: Symposium: High Magnetic Field Phenomena in Low Dimensional Magnets

TT 2.7: Talk

Monday, February 25, 2008, 12:15–12:45, H 0104

Exploring field-induced quantum phase transitions in molecule-based magnets — •Michael Lang¹, Katarina Removic-Langer¹, Yeekin Tsui¹, Ulrich Tutsch¹, Bernd Wolf¹, Andrei Prokofiev¹, Wolf Assmus¹, Roser Valenti², Andreas Honecker³, Matthias Wagner⁴, and Stefan Wessel⁵ — ¹Phys. Inst. Univ. Frankfurt, SFB/TR 49 — ²Inst. f. Theor. Physik, Univ. Frankfurt, SFB/TR 49 — ³Inst. f. Theor. Physik, Univ. Göttingen — ⁴Inst. f. Anorg. u. Analyt. Chemie, Univ. Frankfurt, SFB/TR 49 — ⁵Inst. f. Theor. Physik III, Univ. Stuttgart

Molecule-based quantum magnets offer exciting new possibilities for exploring quantum many-body effects under variable and well-controlled conditions. Subjects of high current interest are the unusual magnetothermal effects close to a magnetic field-induced quantum critical point and the possibility to realize a Bose-Einstein condensation (BEC) of magnetic excitations. We focus here on Cu(II)-containing coordination polymers, which represent model systems with energy scales small enough for laboratory fields to tune the system close to their quantum critical points. We will discuss the magnetocaloric effect close to the saturation field of a uniform S = 1/2 antiferromagnetic Heisenberg chain and the field-induced BEC of magnetic excitations in a quasi-twodimensional coupled-dimer system.