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arXiv · 1803.01193

Evidence for a dynamical ground state in a frustrated pyrohafnate Tb2Hf2O7

V. K. Anand·L. Opherden·J. Xu·D. T. Adroja·A. D. Hillier·P. K. Biswas·T. Herrmannsdörfer·M. Uhlarz·J. Hornung·J. Wosnitza·E. Canevet·B. Lake
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Abstract

We report the physical properties of Tb2Hf2O7 based on ac magnetic susceptibility χ_ac(T), dc magnetic susceptibility χ(T), isothermal magnetization M(H), and heat capacity C_p(T) measurements combined with muon spin relaxation (\muSR) and neutron powder diffraction measurements. No evidence for long-range magnetic order is found down to 0.1 K. However, χ_ac(T) data present a frequency-dependent broad peak (near 0.9 K at 16 Hz) indicating slow spin dynamics. The slow spin dynamics is further evidenced from the \muSR data (characterized by a stretched exponential behavior) which show persistent spin fluctuations down to 0.3 K. The neutron powder diffraction data collected at 0.1 K show a broad peak of magnetic origin (diffuse scattering) but no magnetic Bragg peaks. The analysis of the diffuse scattering data reveals a dominant antiferromagnetic interaction in agreement with the negative Weiss temperature. The absence of long-range magnetic order and the presence of slow spin dynamics and persistent spin fluctuations together reflect a dynamical ground state in Tb2Hf2O7.

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V. K. Anand, L. Opherden, J. Xu, D. T. Adroja, A. D. Hillier, P. K. Biswas, T. Herrmannsdörfer, M. Uhlarz, J. Hornung, J. Wosnitza, E. Canevet, B. Lake. 2018-03-03. Evidence for a dynamical ground state in a frustrated pyrohafnate Tb2Hf2O7. https://doi.org/10.1103/physrevb.97.094402

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