Anomalous thermal expansion and strong damping of the thermal conductivity of NdMnO${}_3$ and TbMnO${}_3$ due to 4f crystal-field excitations

Abstract

We present measurements of the thermal conductivity $\kappa$ and the thermal expansion $\alpha$ of NdMnO${}_3$ and TbMnO${}_3$. In both compounds a splitting of the $4f$ multiplet of the $R^{3+}$ ion causes Schottky contributions to $\alpha$. In TbMnO${}_3$ this contribution arises from a crystal-field splitting, while in NdMnO${}_3$ it is due to the Nd-Mn exchange coupling. Another consequence of this coupling is a strongly enhanced canting of the Mn moments. The thermal conductivity is greatly suppressed in both compounds. The main scattering process at low temperatures is resonant scattering of phonons between different energy levels of the $4f$ multiplets, whereas the complex 3d magnetism of the Mn ions is of minor importance.

9 pages including 6 figures

References in corpus (4)

• Neutron diffraction study of TbMnO3: Magnetic structure revisited
• New features in the phase diagram of TbMnO${}_3$
• Spin thermal conductivity of the Haldane chain compound Y2BaNiO5
• Thermodynamics of the coupled spin-dimer system TlCuCl3 close to a quantum phase transition

Cited by in corpus (12)

• Large magnetothermal conductivity of HoMnO_3 single crystals and its relation to the magnetic-field induced transitions of magnetic structure
• Directly probing spin dynamics in insulating antiferromagnets using ultrashort terahertz pulses
• Room-temperature Magnetic Thermal Switching by Suppressing Phonon-Magnon Scattering
• Phonon thermal Hall effect in non-magnetic Y${}_2$Ti${}_2$O${}_7$
• Magneto-thermal evidence of a partial gap at the Fermi surface of UPt_2Si_2
• Modifying the magnetoelectric coupling in TbMnO${}_3$ by low-level Fe${}^{3+}$ substitution
• Abnormally enhanced Hall Lorenz number in the magnetic Weyl semimetal NdAlSi
• Magnetoelastic coupling and Grüneisen scaling in NdB${}_4$
• Photoinduced structural dynamics of multiferroic TbMnO${}_3$
• Scaling behavior and giant field-enhancement of the thermal conductivity in the honeycomb antiferromagnet BaCo2(AsO4)2
• Suppression of Thermal Conductivity via Singlet-Dominated Scattering in TmFeO${}_3$
• Nonreciprocal thermal transport in a multiferroic helimagnet