Naslov
The role of magnetic excitations in the thermal conductivity of the frustrated spin system Cu2Te2O5(Cl2-xBrx) system

Autori
Bilušić, Ante ; Smontara, Ana ; Smiljanić, Igor ; Jagličić, Zvonko ; Dolinšek, Janez ; Berger, Helmuth

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Highly Frustrated Magnetism / Bramwell, S ; Keren, A ; Mila, F. - Pariz : Centre National de la Recherche Scientifique, 2005, 62-62

Skup
ESF Workshop "Highly Frastrated Magnetism"

Mjesto i datum
La Londe-les-Maures, Francuska, 07.11.2005. - 09.11.2005

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
copper-tellurides; frustrated spin systems; magnetic phase transition; thermal conductivity

Sažetak
Insulating copper-tellurides of the general formula Cu2Te2O5(Cl2-xBrx) belong to the class of geometrically frustrated spin systems due to the tetrahedral arrangement of Cu2+ ions [1]. Specific heat [2] and magnetic susceptibility data [2, 3] show that between 11.4 K and 18.2 K (depending on the Br content) copper-tellurides exhibit a magnetic phase transition. A long-range spin-ordered state is formed below the transition temperature, as proven by the Raman [4, 5] and neutron [6] experiments. We present the thermal conductivity data of copper-tellurides Cu2Te2O5(Cl2-xBrx), with x=0, 0.5, 1, and 2. For temperatures higher than the transition temperature, thermal conductivity has a rather low value. Numerical analysis of the thermal conductivity curves, based on of the Debye model, show that a resonant magneto-elastic coupling takes part in the phonon scattering. Below the transition temperature, thermal conductivitie rapidly increases with decreasing temperature. We propose, that after a formation of the long-range spin ordered state a magneto-elastic resonant scattering is switched off, leading to the enhanced thermal conductivity. Renormalization of the thermal conductivity data show that the thermal conductivity enhancement is the most pronounced in the x=2 system, and is lowered as the Br-content is reduced.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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