Temperature and magnetic field dependence of spin-ice correlations in the pyrochlore magnetTb2Ti2O7
| Autor: | H. A. Dabkowska, K. Fritsch, Jan Kycia, Yiming Qiu, D. Pomaranski, Bruce D. Gaulin, Kathryn Aileen Ross, John R. D. Copley, E. Kermarrec |
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| Rok vydání: | 2014 |
| Předmět: |
Physics
Spin glass Condensed matter physics Spin polarization Order (ring theory) 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials Spin ice Brillouin zone 0103 physical sciences Antiferromagnetism Quantum spin liquid 010306 general physics 0210 nano-technology Ground state |
| Zdroj: | Physical Review B. 90 |
| ISSN: | 1550-235X 1098-0121 |
| DOI: | 10.1103/physrevb.90.014429 |
| Popis: | We present a parametric study of the diffuse magnetic scattering at $(\frac{1}{2},\frac{1}{2},\frac{1}{2})$ positions in reciprocal space, ascribed to a frozen antiferromagnetic spin ice state in single-crystalline ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$. Our high-resolution neutron scattering measurements show that the elastic $(\ensuremath{-}0.02$ meV $lEl0.02$ meV) $(\frac{1}{2},\frac{1}{2},\frac{1}{2})$ scattering develops strongly below $\ensuremath{\approx}$275 mK, and correlates with the opening of a spin gap of $\ensuremath{\approx}0.06$ to 0.08 meV over most of the Brillouin zone. The nature of the transition at 275 mK has many characteristics of spin glass behavior, consistent with ac-susceptibility measurements. The application of a magnetic field of 0.075 T applied along the $[1\overline{1}0]$ direction destroys the $(\frac{1}{2},\frac{1}{2},\frac{1}{2})$ elastic scattering, revealing the fragility of this short-range ordered ground state. We construct a refined $H$-$T$ phase diagram for ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ and $[1\overline{1}0]$ fields which incorporates this frozen spin ice regime and the antiferromagnetic long-range order previously known to be induced in relatively large fields. Specific heat measurements on the same crystal reveal a sharp anomaly at ${T}_{\mathrm{c}}\ensuremath{\approx}$ 450 mK and no indication of a transition near $\ensuremath{\approx}$275 mK. We conclude that the higher temperature specific heat peak is not related to the magnetic ordering but is likely a signal of other, nonmagnetic dipole correlations. |
| Databáze: | OpenAIRE |
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