Ba₃La₂Ti₂Ta₂O₁₅: A new microwave dielectric of A₅B₄O₁₅-type cation-deficient perovskites

Abstract

The synthesis, structure and properties of a new A₅B₄O₁₅-type cation-deficient perovskite Ba₃La₂Ti₂Ta₂O₁₅ were discribed. The compound was prepared by the conventional solid-state reaction route. The phase and structure of the ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The results reveal that the compound is successfully synthesized. The compound crystallizes in the trigonal system with unit cell parameter a=5.6730(2) Å, c=11.6511(2) Å, V=324.93(1) ų and Z=1. The microwave dielectric properties of the ceramic are studied using a network analyzer, and it shows a high dielectric constant of 45.1, a high quality factors with Q×f of 21 029 GHz, and a positive τ _f of 5.3 ppm°C⁻¹.

Keywords

X-ray diffraction / dielectric resonators / microwave ceramics / hexagonal perovskites

References

[1] Wersing W. Microwave Ceramics for Resonators and Filters[J]. Current Opinion in Solid State Materials Science, 1996, 1: 715-731.

[2] Ubic R., Reaney I. M., Lee W. E. Microwave Dielectric Solid-Solution Phase in System Bao-Ln₂O₃-TiO₂[J]. International Materials Reviews, 1998, 43(5): 205-219.

[3] Sebastian M T. New Low Loss Microwave Dielectric Ceramics in the BaO-TiO₂-Nb₂O₅/Ta₂O₅ System[J]. Journal of Materials Science: Materials in Electronics, 1999(10):475–478

[4] Ratheesh R., Sreemoolanadhan H., Suma S., . New High Permittivity and Low Loss Ceramics in the BaO-TiO₂-Nb₂O₅ Composition[J]. J. Materials Science: Materials in Electronics, 1998, 9: 291-294.

[5] Fang L., Zhang H., Yang J. F., . Preparation, Characterization and Dielectric Properties of Ba₅LnZnTa₉O₃₀(Ln=La,Sm) Ceramics[J]. Materials Research Bulletin, 2004, 39(4): 677-682.

[6] Zhang H., Fang L., Dronskowski R., . Some A₆B₅O₁₈ Cation-deficient Perovskites in the BaO-La₂O₃-TiO₂-Nb₂O₅ System[J]. J. Solid State Chem., 2004, 177: 4 007-4 012.

[7] Zhang H., Fang L., Yang J. F., . Characterization and Dielectric Properties of Ba₅NdZnM₉O₃₀(M=Nb,Ta) Ceramics[J]. Journal of Materials Science: Materials in Electronics, 2004, 15(5): 327-329.

[8] Fang L., Zhang H., Yang J. F., . Preparation, Characterization and Dielectric Properties of Sr₅LnTi₃Ta₇O₃₀(Ln=La,Nd) Ceramics[J]. Journal of Materials Science: Materials in Electronics, 2004, 15(6): 355-357.

[9] Fang L., Meng S.-s., Zhang H., . Ba₂La₂TiNb₂O₁₂: A New Microwave Dielectric of A₄B₃O₁₂-type Cation-deficient Perovskites[J]. Materials Letters, 2006, 60(9–10): 1 147-1 150.

[10] Ratheesh R., Sebastian M. T., Mohanan P., . Microwave Characterization of BaCe₂Ti₅O₁₅ and Ba₅Nb₄O₁₅ Ceramic Dielectric Resonators Using Whispering Gallery Mode Method[J]. Materials Letters, 2000, 45: 279-285.

[11] Sreemoolanadhan H., Sebastian M. T., Mohanan P. High Permittivity and Low Loss Ceramics in the BaO-SrO-Nb₂O₅ System[J]. Mater.Res.Bull., 1995, 30: 653-658.

[12] Vineis C., Davies P. K. Microwave Dielectric Properties of Hexagonal Perovskites[J]. Mater. Res. Bulletin, 1996, 31(5): 431-437.

[13] Jawahar I. N., Santha N. I., Sebastian M. T. Microwave Dielectric Properties of MO-La₂O₃-TiO₂ (M=Ca, Sr, Ba) Ceramics[J]. J. Materials Research, 2002, 17: 3 084

[14] Fang L., Diao C. L., Zhang H., . Preparation and Characterization of Two New Dielectric Ceramics Ba₄NdTiNb₃O₁₅ and Ba₃Nd₂Ti₂Nb₂O₁₅[J]. J. Mat. Sci: Mater. Electron, 2004, 15(12): 803-805.

[15] Fang L., Zhang H., Huang T. H., . Preparation, Structure and Dielectric Properties of Ba₄LaMNb₃O₁₅(M= Ti, Sn) Ceramics[J]. Materials Research Bulletin, 2004, 39(11): 1 649-1 654.

[16] L FANG, S S MENG, H ZHANG, et al. Structural and Microwave Dielectric Properties of Ba_5−xLaxTi_xNb_4−xO₁₅ Ceramics[J]. Journal of Electroceramics, 10.1007/s10832-007-9097-3

[17] Fang L., Zhang H., Hong X. K., . Preparation and Characterization of Two New Dielectric Ceramics Ba₃La₂Ti₂Nb₂O₁₅ and Ba₂La₃Ti₃NbO₁₅[J]. Materials Letters, 2004, 58(30): 3 884-3 887.

[18] Hakki B W, Coleman P D. A Dielectric Resonator Method of Measuring Inductive Capacities in the Millimeter Range[J]. IEEE Trans. Microwave Theory Tech., 1960, 8: MIT

[19] Courthney W. E. Analysis and Evaluation of a Method of Measuring the Complex Permittivity and Permeability of Microwave Insulators[J]. IEEE Trans. Microwave Theory Tech., 1970, MIT-18: 476