Tunability and dielectric properties of Ba0.55Sr0.45TiO3/MgO composites prepared by heterogeneous precipitation method and sol-gel method

45wt% Ba0.55Sr0.45TiO3-55wt% MgO composites prepared by heterogeneous precipitation method and sol-gel method were synthesized. Coating layer was obviously observed in the calcined BST/MgO particles prepared by heterogeneous precipitation method and sol-gel method, but it disappeared in the composites after sintering because of the grain growth of MgO. Compared to the sample prepared by conventional solid-state reaction method, higher tunability and higher dielectric constant while lower dielectric loss was achieved in the BST/MgO composites prepared by heterogeneous precipitation method and sol-gel method. This result was attributed to the difference of Mg element content in BST grain. This study shows that using the heterogeneous precipitation and sol-gel method effectively improved the properties of the BST/MgO composites.