Correlation between dielectric loss, microstructures and phase structures in a novel Mgn+1TinO3n+1 microwave ceramic system

Phase compositions, microstructures and microwave dielectric properties of the MgTiO3 and Mgn+1TinO3n+1 (1 ≤ n ≤ 7, 50) specimens prepared via the conventional solid-state reaction route were investigated. X-ray patterns revealed that a certain amount of the Mgn+1TinO3n+1 phases were detected in the specimens with n = 2-5. Additionally, a visualization of the MgTiO3, Mg2TiO4 unit cell and the considered Mg-Ti-O layered supercells were described, and the layered rhombohedral Mg-Ti-O phases were supposed to make the crystal structure more stable. Both EDS and Raman spectrum analysis results proved that the Mgn+1TinO3n+1 (2 ≤ n ≤ 5) phases indeed existed in the present systems. Besides, the Q×f value was extremely sensitive to the analogical layered phases content and compactness. A relative higher content of Mgn+1TinO3n+1 (2 ≤ n ≤ 5) phases and a well-developed microstructure could cause an extremely low dielectric loss in these ceramic systems. Moreover, some very high Q×f values (>300,000 GHz) could also be achieved for the Mgn+1TinO3n+1 (n = 6, 7) systems as well. Thus, the Mgn+1TinO3n+1 ceramic systems were expected to substitute for conventional MgTiO3 or Mg2TiO4 systems to form some novel microwave dielectric materials with the ultralow dielectric loss.