Modelling Dynamical Fluorescent Micro Thermal Imaging of the Heat Diffusion in the La5Ca9Cu24O41 Spin Ladder Compound

The dynamical fluorescent microthermal imaging (FMI) experiment has been used to investigate the phonon-magnon interaction in the 1D Heisenberg antiferromagnet La5Ca9Cu24O41. This material shows highly anisotropic heat conductivity due to the efficient magnetic heat transport along the spin ladders in the compound. To extract information on the phonon-magnon interaction we modelled the dynamic heat transport experiment using a two temperature model approach, taking both the crystal as well as the PMMA/EuTTA fluorescent heat imaging layer into account. The simulations are carried out by the finite element method using COMSOL Multiphysics Heat Transfer Module. The results of the numerical calculations are expected to be used for the data analysis of the experimental studies.