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MA: Fachverband Magnetismus
MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)
MA 15.132: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Heat conduction in spin-gap antiferromagnets — Igor Smiljanić1, •Ante Bilušić1,2, Ana Smontara1, Helmuth Berger3, and László Forró3 — 1Institute of Physics, Zagreb, Croatia — 2Faculty of Science, Univ. of Split, Croatia — 3Ecole Polytechnique Fédérale de Lausanne, Switzerland
Spin-gap antiferomagnets (SG AFMs) have a discrete spin-energy spectrum due to the existence of short-range spin correlations only. The thermal conductivity of SG AFMs is a tool that probes their spin excitations and spins-phonons interaction. A variety of phenomena are observed: for example, in various strontium-cuprates thermal conductivity strongly enhances due to the opening of the heat channel carried by either magnons or spinons. In spin-Peierls compounds the thermal conductivity exhibits rather unusual double peak features at low temperatures, explained as a fingerprint of the spin-phonon resonance scattering. The thermal conductivity of strongly frustrated systems also shows the existence of spin-phonon resonance at low temperatures. We present the study of the thermal transport of several SG AFMs: (i) of copper-tellurides, quasi-0D geomatrically frustrated compounds with S=1/2, (b) of a "zig-zag" frustrated spin ladder system LiCu2O2 (S=1/2), and (c) quasi-2D S=1 system nickel-telluride. We find that the thermal conductivity of these systems exhibit features typical for spin-phonon resonance coupling, gradually decreasing as the dimensionality of the systems increase. This work was done within the SNF SCOPES project No. IB7320-111044.