The Electromagnetic Property Of Giant Dielectric CSTF-CBO(B=Ti,Mn) Ceramic

Dielectric materials are the central material of electronic and microelectronic devices, the rapid development of electric technology asks the electronic components for better performance, which need dielectric materials with better property. Giant dielectric material refers to the materials whose dielectric constant is greater than 1000, because of its large constant. The electronic components made by giant dielectric material can store more charge and energy in a smaller volume scale, so that the size of device reduce greatly, and the integration level improved greatly.Although the dielectric constant of many dielectric materials has been fully sufficient to achieve the miniaturization of the device, but it is not practical because of its poor temperature stability. Then people found that there is a giant dielectric constant step in Ca Cu3Ti4O12 and complex perovskites A(Fe0.5B0.5)O3(A=Ba, Ca, Sr; B=Ta, Nb, Sb), many studies are carried out on this phenomenon. In the experiment, we found that there is also a giant dielectric constant step in CSTF-CBO(B=Ti, Mn) composite ceramics just like that in Ca Cu3Ti4O12, so it has a giant dielectric constant and a good temperature stability. It is necessary to do a through research on its property to explain the giant dielectric constant step.In the present thesis, CSTF-CBO(B=Ti, Mn) composite ceramics were prepared by conventional solid-state reaction method firstly, the process of preparation was introduced in detail. Then the microscopic morphology was observed by scanning electron microscopy, the structure of grain, compactness and phase were also analyzed. Then the microstructure was studied, the phase structure and their change versus component by analyzing X-ray diffraction pattern.Then the dielectric property of CSTF-CBO(B=Ti, Mn) was studied. The temperature dependence of dielectric constant and dielectric loss was measured, and the activation energy was obtained by analyzing the position of dielectric loss peak. The element valence was investigated by X-ray photoelectron spectroscopy, then the origin of the dielectric relaxation and its change versus component were given. Origin of the giant dielectric constant and the giant dielectric constant step were also explained.Finally, the hysteresis loop of CSTF-CBO(B=Ti, Mn) was measured by vibrating sample magnetometer, the change law between magnetism and component was displayed and the reason was given. The relative permittivity and relative permeability in the microwave region were measured and the reflection loss of the ceramics was caculated, the microwave absorption property of the ceramic was charactered.