Low-temperature heat transport of Nd2CuO4: Roles of Nd magnons and spin-structure transitions.

We report the magnetic-field dependence of thermal conductivity (κ) of an insulating cuprate Nd2CuO4 at very low temperatures down to 0.3 K. It is found that, apart from the paramagnetic moments scattering on phonons, the Nd3+ magnons can act as either heat carriers or phonon scatterers, which strongly depends on the long-range antiferromagnetic transition and the field-induced transitions of spin structure. In particular, the Nd3+ magnons can effectively transport heat in the spin-flopped state of the Nd3+ sublattice. However, both the magnon transport and the magnetic scattering are quenched at very high fields. The spin reorientations under the in-plane field can be conjectured from the detailed field dependence of ?. [ABSTRACT FROM AUTHOR]