Optothermal Raman measurement determined thermal conductivity characteristics in NiMn2O4 films grown by chemical solution deposition

Abstract NiMn 2 O 4 (NMO) thin films with different thicknesses (0.47–1.90 μ m) were grown on Yttria-stabilized zirconia (YSZ)(100) substrates by chemical solution deposition (CSD). The effects of different growth conditions on the structural and thermal properties of NMO films were investigated. X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements show that both the average grain size of the samples and the surface roughness become larger with an increase of thickness. Based on isothermal surface condition, the corresponding thermal conductivity of NMO films was extracted from the optothermal Raman measurement and the obtained thermal conductivity is ∼4.0 ± 0.8 W m −1 K −1 for micrometer-scale films, suggesting that the (grain) boundary phonon scattering plays a minor role to affect the thermal conductivity of thin NMO films.