Preparation and Properties of La_2O_3 Doped BST/Mg_2TiO_4 Microwave Composite Ceramics
La_2O_3掺杂BST/Mg_2TiO_4微波复合陶瓷的制备和性能

La2O3 doped Ba0.55Sr0.45TiO3/Mg2TiO4 microwave composite ceramics were prepared by traditional solid-state reaction, and the influence of La2O3 doping on microstructure, dielectric properties and tuning was investigated. The results show that La3+ enters BST lattices when the mass fraction of La2O3 reach 1.2%, and La3+ doped sample can prevent the change of the chemical valence of Ti in BST/Mg2TiO4 composite system from +4 to +3. Mg2TiO4 and La2O3 doping can reduce the dielectric constant and microwave loss separately. The 1.2% La2O3 doped sample has the best properties: dielectric constant 52; tanδ 0.0011 (10 GHz), and the tunability 13.4% (3 kV/mm).