XY antiferromagnetic ground state in the effectiveS=12pyrochloreYb2Ge2O7
| Autor: | R. S. Freitas, C. R. Wiebe, J. P. Attfield, Matthew B. Stone, Graeme Luke, Alannah Hallas, Bruce D. Gaulin, Jonathan Gaudet, M. N. Wilson, Adam A. Aczel, Makoto Tachibana, Angel M. Arevalo-Lopez, Timothy J. S. Munsie |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
Magnetic moment Condensed matter physics Neutron diffraction Pyrochlore 02 engineering and technology Muon spin spectroscopy engineering.material Neutron scattering 021001 nanoscience & nanotechnology 01 natural sciences Inelastic neutron scattering 0103 physical sciences engineering Antiferromagnetism 010306 general physics 0210 nano-technology Ground state |
| Zdroj: | Physical Review B. 93 |
| ISSN: | 2469-9969 2469-9950 |
| Popis: | We report neutron scattering and muon spin relaxation measurements ($\ensuremath{\mu}\mathrm{SR}$) on the pyrochlore antiferromagnet ${\mathrm{Yb}}_{2}{\mathrm{Ge}}_{2}{\mathrm{O}}_{7}$. Inelastic neutron scattering was used to probe the transitions between crystal electric field levels, allowing us to determine the eigenvalues and eigenvectors appropriate to the $J=\frac{7}{2}\phantom{\rule{4pt}{0ex}}{\mathrm{Yb}}^{3+}$ ion in this environment. The crystal electric field ground state doublet in ${\mathrm{Yb}}_{2}{\mathrm{Ge}}_{2}{\mathrm{O}}_{7}$ corresponds primarily to ${m}_{J}=\ifmmode\pm\else\textpm\fi{}\frac{1}{2}$ with local XY anisotropy, consistent with an ${S}_{\text{eff}}=\frac{1}{2}$ description for the Yb moments. $\ensuremath{\mu}\mathrm{SR}$ measurements reveal the presence of an ordering transition at ${T}_{N}=0.57$ K with persistent weak dynamics in the ordered state. Finally, we present neutron diffraction measurements that reveal a clear phase transition to the $\mathbf{k}=(000)\phantom{\rule{4pt}{0ex}}{\mathrm{\ensuremath{\Gamma}}}_{5}$ ground state with an ordered magnetic moment of $0.3(1){\ensuremath{\mu}}_{B}$ per Yb ion. We compare and contrast this phenomenology with the low-temperature behavior of ${\mathrm{Yb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ and ${\mathrm{Er}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$, the prototypical ${S}_{\text{eff}}=\frac{1}{2}$ XY pyrochlore magnets. |
| Databáze: | OpenAIRE |
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