engleski

Heat conduction in spin-gap antiferromagents

The thermal conductivity of materials with magnetic interaction is a valuable tool that probes their spin excitations and spin interaction to other subsystems (like phonons). 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 and strongly frustrated compounds the thermal conductivity exhibits rather unusual double peak features at low temperatures, explained as a fingerprint of the spin-phonon resonance scattering. We present the study of the thermal transport of several spin-gap antiferromagnets: (i) copper-tellurides, quasi-0D geomatrically frustrated compounds with S=1/2, (b) "zig-zag" frustrated spin ladder system LiCu_2O_2 (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 system increase.

thermal conductivity; spin gap system

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