Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 78: Correlated Electrons: Poster Session
TT 78.51: Poster
Donnerstag, 10. März 2016, 15:00–18:30, Poster D
Field-induced ordered phases in the tetragonal quasi-2d dimer system Ba0.9Sr0.1CuSi2O6 — •Lars Postulka, Bernd Wolf, Pascal Puphal, Natalija Van Well, Franz Ritter, Cornelius Krellner, and Michael Lang — Goethe-Univeristät, Physikalisches Institut SFB/TR49, D-60438 Frankfurt(M),Germany
Magnetic compounds built of antiferromagnetically-coupled S = 1/2 dimers, allow to study finite-temperature critical phenomena under well-controlled conditions, including Luttinger-liquid, Berezinskii-Kosterlitz-Thouless-type topological order as well as Bose-Einstein-condensation of triplons.
A material of high interest within this context is the quasi-2d coupled-dimer system BaCuSi2O6, which shows a field-induced ordered state exhibiting the signatures of a dimensional reduction [1]. This has been assigned to perfectly frustrated interlayer couplings, but has been questioned by Sheptyakov et al. since the system undergoes a tetragonal to orthorhombic phase transition at 100 K below which two different types of dimer layers exist [2]. Here we report magnetic properties of Ba0.9Sr0.1CuSi2O6 where the structural phase transition has been suppressed by strontium doping. We show results on magnetic susceptibility measurements as a function of temperature between 2 K < T < 300 K as well as field-dependant measurements up to B < 50 T at T = 1.5 K. We estimate the magnetic couplings and compare the results with those of the well-known parent compound BaCuSi2O6.
S. E. Sebastian et al., Nature 441, 617 (2006)
D. V. Sheptyakov et al., PRB 86, 014433 (2012)