Journal Article

PreJuSER-15570

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Magnetic correlations in HoxTb2-xTi2O7

Chang, L. J. ; Schweika, W.FZJ* ; Kao, Y.-J. ; Chou, Y. Z. ; Perßon, J.FZJ* ; Brückel, T.FZJ* ; Yang, H. C. ; Chen, Y. Y. ; Gardner, J. S.

2011
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/10936  doi:10.1103/PhysRevB.83.144413

Abstract: Polycrystalline samples of HoxTb2-xTi2O7 (0 < x < 2) have been prepared and characterized for their structural and magnetic properties. The parent compounds of this solid solution are the spin ice Ho2Ti2O7 and the spin liquid Tb2Ti2O7. Specific-heat measurements on HoTbTi2O7 (x = 1.0) reveal the absence of a long-range order state above 0.5 K. The integrated entropies of all HoxTb2-xTi2O7 specimens up to 30 K scale well with the ratio of spin ice and spin liquid in the composition. The neutron diffraction spectrum of HoTbTi2O7 exhibits a dipolar spin-ice pattern and can be well described by mean-field theory for < 111 > Ising spins, nearest-neighbor exchange, and dipolar interactions. Inelastic neutron scattering on HoTbTi2O7 reveals two dispersionless excitations, one of similar to 2.5 meV out of the ground state, and a 4-meV transition out of an excited state. We argue that these data suggest that the very strong single-ion effects of Ho2Ti2O7 and Tb2Ti2O7 persist in the HoxTb2-xTi2O7(0 < x < 2) solid solution, whereas the Tb-Ho correlations are weak, resulting in small shifts in the energy scales but with no dramatic effect on the bulk properties.

Keyword(s): J

Note: This work was supported in Taiwan by Grants No. NSC 96-2739-M-213-001, No. NSC 99-2112-M-007-020 (LJC), No. NSC 97-2628-M-002-011-MY3, and No. NTU 98R0066-65, -68 (Y.Z.C. and Y.J.K.).

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Contributing Institute(s):

1. Streumethoden (PGI-4)
2. Streumethoden (JCNS-2)
3. Jülich-Aachen Research Alliance - Fundamentals of Future Information Technology (JARA-FIT)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)
2. Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) (P55)

Experiment(s):

1. DNS: Diffuse scattering neutron time of flight spectrometer (NL6S)

Appears in the scientific report 2011

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