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

Phase-pure CaMoO4 microwave dielectric ceramic was sintered at 1150 celcius for 4 h via a conventional solid-state reaction method, which was indicated as a tetragonal scheelite structure (space group I4(1)/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 E-u modes, i.e., translational vibration of Ca-O bonds in the CaMoO4 ceramic.