Tuning interactions in the spin-ice materials Dy$_2$Ge$_{2-x}$Si$_x$O$_7$ by silicon substitution
| Autor: | Stöter, T., Antlauf, M., Opherden, L., Gottschall, T., Hornung, J., Gronemann, J., Herrmannsdörfer, T., Granovsky, S., Schwarz, M., Doerr, M., Klauss, H. -H., Kroke, E., Wosnitza, J. |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 100, 054403 (2019) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.100.054403 |
| Popis: | We report that the lattice constant of Dy$_2$Ge$_{2-x}$Si$_x$O$_7$ ($x=0, 0.02, 0.08, 0.125$) can be systematically reduced by substituting the non-magnetic germanium ion in the cubic pyrochlore oxide with silicon. A multi-anvil high-pressure synthesis was performed up to 16 GPa and 1100 $^\circ$C to obtain polycrystalline samples in a solid-state reaction. Measurements of magnetization, ac susceptibility, and heat capacity reveal the typical signatures of a spin-ice phase. From the temperature shift of the peaks, observed in the temperature-dependent heat capacity, we deduce an increase of the strength of the exchange interaction. In conclusion, the reduced lattice constant leads to a changed ratio of the competing exchange and dipolar interaction. This puts the new spin-ice compounds closer towards the phase boundary of short-range spin-ice arrangement and antiferromagnetic long-range order consistent with an observed reduction of the monopole energy scale. Comment: 6 pages, 6 figures |
| Databáze: | arXiv |
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