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arXiv · 0806.1617

Optical spectra of the heavy fermion uniaxial ferromagnet UGe$_2$

V. Guritanu·N. P. Armitage·R. Tediosi·S. S. Saxena·A. Huxley·D. van der Marel
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Abstract

We report a detailed study of UGe$_{2}$ single crystals using infrared reflectivity and spectroscopic ellipsometry. The optical conductivity suggests the presence of a low frequency interband transition and a narrow free-carrier response with strong frequency dependence of the scattering rate and effective mass. We observe sharp changes in the low frequency mass and scattering rate below the upper ferromagnetic transition $T_C = 53 K$. The characteristic changes are exhibited most strongly at an energy scale of around 12 meV (100 cm$^{-1}$). They recover their unrenormalized value above $T_C$ and for $ω>$ 40 meV. In contrast no sign of an anomaly is seen at the lower transition temperature of unknown nature $T_x \sim$ 30 K, observed in transport and thermodynamic experiments. In the ferromagnetic state we find signatures of a strong coupling to the longitudinal magnetic excitations that have been proposed to mediate unconventional superconductivity in this compound.

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V. Guritanu, N. P. Armitage, R. Tediosi, S. S. Saxena, A. Huxley, D. van der Marel. 2008-06-10. Optical spectra of the heavy fermion uniaxial ferromagnet UGe$_2$. https://doi.org/10.1103/physrevb.78.172406

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