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Inhomogeneous level splitting in Pr$_{2-x}$Bi$_x$Ru$_2$O$_7$

J. van Duijn·K. H. Kim·N. Hur·D. Adroja·M. A. Adams·Q. Z. Huang·M. Jaime·S. -W. Cheong·C. Broholm·T. G. Perring
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Abstract

We report that Bi doping drives Pr$_x$Bi$_{2-x}$Ru$_2$O$_7$ from an antiferromagnetic insulator ($x=2$) to a metallic paramagnet ($x\approx 1$) with a broad low $T$ maximum in $C/T$. Neutron scattering reveals local low energy spin excitations ($\hbarω\approx 1$ meV) with a spectrum that is unaffected by heating to $k_BT>>\hbarω$. We show that a continuous distribution of splittings of the non-Kramers Pr$^{3+}$ ground state doublet such as might result from various types of lattice strain can account for all the data.

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J. van Duijn, K. H. Kim, N. Hur, D. Adroja, M. A. Adams, Q. Z. Huang, M. Jaime, S. -W. Cheong, C. Broholm, T. G. Perring. 2005-05-03. Inhomogeneous level splitting in Pr$_{2-x}$Bi$_x$Ru$_2$O$_7$. https://doi.org/10.1103/physrevlett.94.177201

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