Anisotropic Monopole Heat Transport in the Spin-Ice Compound Dy$_2$Ti$_2$O$_7$
| Autor: | Kolland, G., Valldor, M., Hiertz, M., Frielingsdorf, J., Lorenz, T. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 88, 054406 (2013) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.88.054406 |
| Popis: | We report a study of the thermal conductivity $\kappa$ of the spin-ice material Dy$_2$Ti$_2$O$_7$. From the anisotropic magnetic-field dependence of \kappa$ and by additional measurements on the phononic reference compounds Y$_2$Ti$_2$O$_7$ and DyYTi$_2$O$_7$, we are able to separate the phononic and the magnetic contributions to the total heat transport, i.e. $\kappa_{ph}$ and $\kappa_{mag}$, respectively, which both depend on the magnetic field. The field dependent $\kappa_{ph}$ arises from lattice distortions due to magnetic-field induced torques on the non-collinear magnetic moments of the Dy ions. For $\kappa_{mag}$, we observe a highly anisotropic magnetic-field dependence, which correlates with the corresponding magnetization data reflecting the different magnetic-field induced spin-ice ground states. The magnitude of $\kappa_{mag}$ increases with the degree of the ground-state degeneracy. This anisotropic field dependence as well as various hysteresis effects suggest that $\kappa_{mag}$ is essentially determined by the mobility of the magnetic monopole excitations in spin ice. Comment: 8 pages, 5 figures |
| Databáze: | arXiv |
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