Phonon characteristics and intrinsic properties of phase-pure CaMoO4 microwave dielectric ceramic

Phase-pure CaMoO4 microwave dielectric ceramic was sintered at 1150 ℃ for 4 h via a conventional solid-state reaction method, which was indicated as a tetragonal scheelite structure (space group I41/a) by XRD analysis. Raman scattering and infrared spectra of the phase-pure CaMoO4 were investigated based on Lorentz function, four-parameter semiquantum model and Kramers–Kronig transformation to reveal the local structure and intrinsic properties. External modes of Raman spectrum are vibration of Ca2+ ions relative to the rigid [MoO4]2− tetrahedron, internal modes corresponded to vibration inside [MoO4]2−. Fitting infrared spectrum show that the dielectric properties are similar to the experimental results and the main source of contribution to dielectric response comes from Eu modes, i.e., translational vibration of Ca–O bonds in the CaMoO4 ceramic.