Tuning interactions in the spin-ice materials Dy$_2$Ge$_{2-x}$Si$_x$O$_7$ by silicon substitution

T. Stöter; M. Antlauf; L. Opherden; T. Gottschall; J. Hornung; J. Gronemann; T. Herrmannsdörfer; S. Granovsky; M. Schwarz; M. Doerr; H. -H. Klauss; E. Kroke; J. Wosnitza

doi:10.1103/PhysRevB.100.054403

paper

Tuning interactions in the spin-ice materials Dy $_{2}$ Ge $_{2 - x}$ Si $_{x}$ O $_{7}$ by silicon substitution

arXiv:1809.01480 · doi:10.1103/PhysRevB.100.054403

Abstract

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.

arXiv comment6 pages, 6 figures

Tuning interactions in the spin-ice materials Dy2​Ge2−x​Six​O7​ by silicon substitution

Abstract

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Tuning interactions in the spin-ice materials Dy $_{2}$ Ge $_{2 - x}$ Si $_{x}$ O $_{7}$ by silicon substitution