تقرير
Neutron Spectroscopic Study of Crystalline Electric Field Excitations in Stochiometric and Lightly Stuffed Yb2Ti2O7
| العنوان: | Neutron Spectroscopic Study of Crystalline Electric Field Excitations in Stochiometric and Lightly Stuffed Yb2Ti2O7 |
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| المؤلفون: | Gaudet, J., Maharaj, D. D., Sala, G., Kermarrec, E., Ross, K. A., Dabkowska, H. A., Kolesnikov, A. I., Granroth, G. E., Gaulin, B. D. |
| المصدر: | Phys. Rev. B 92, 134420 (2015) |
| سنة النشر: | 2015 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Strongly Correlated Electrons |
| الوصف: | Time-of-flight neutron spectroscopy has been used to determine the crystalline electric field (CEF) Hamiltonian, eigenvalues and eigenvectors appropriate to the $J$ = 7/2 Yb$^{3+}$ ion in the candidate quantum spin ice pyrochlore magnet $\rm Yb_2Ti_2O_7$. The precise ground state (GS) of this exotic, geometrically-frustrated magnet is known to be sensitive to weak disorder associated with the growth of single crystals from the melt. Such materials display weak "stuffing" wherein a small proportion, $\approx$ 2\%, of the non-magnetic Ti$^{4+}$ sites are occupied by excess Yb$^{3+}$. We have carried out neutron spectroscopic measurements on a stoichiometric powder sample of Yb$_2$Ti$_2$O$_7$, as well as a crushed single crystal with weak stuffing and an approximate composition of Yb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ with $x$ = 0.046. All samples display three CEF transitions out of the GS, and the GS doublet itself is identified as primarily composed of m$_J$ = $\pm$1/2, as expected. However,"stuffing" at low temperatures in Yb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ induces a similar finite CEF lifetime as is induced in stoichiometric Yb$_2$Ti$_2$O$_7$ by elevated temperature. We conclude that an extended strain field exists about each local "stuffed" site, which produces a distribution of random CEF environments in the lightly stuffed Yb$_{2+x}$Ti$_{2-x}$O$_{7+y}$, in addition to producing a small fraction of Yb-ions in defective environments with grossly different CEF eigenvalues and eigenvectors. Comment: 11 pages, 9 figures, 4 tables |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevB.92.134420 |
| URL الوصول: | http://arxiv.org/abs/1507.08200 |
| رقم الأكسشن: | edsarx.1507.08200 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevB.92.134420 |
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