Effects of various manganese dopants on dielectric properties of BST-MgO ceramics

0.45Ba0.55Sr0.45TiO3-0.55MgO-Mn(NO3)2/MnCO3(BST-MgO for short) ceramics were prepared by the traditional solid-state reaction method.The effects of various manganese dopants(solid MnCO3 and liquid Mn(NO3)2)on the densification behavior and the microwave dielectric properties of the prepared BST-MgO ceramics were investigated.The results show that compared with solid MnCO3 doping,liquid Mn(NO3)2 doping can improve the probability of Mn ion to diffuse into BST lattcie and degrade the solubility of Mg2+ in BST,which subsquently increases the density and reduces dielectric loss of the BST-MgO ceramics.The ceramics doped with Mn(NO3)2 exhibit relatively better dielectric properties: er=116,tanδ=0.003 8,Tu=19.64%,K=51.68 at 10 kHz and Q?f=788 GHz at 3 GHz.