铌酸盐材料的介电性能研究材料科学与工程专业论文.docxVIP

优秀毕业论文 精品参考文献资料 AbstractAb Abstract Ab stract With the development of the industry in micro·-electronics and energy-—storage materials，dielectric functional materials have become new frontier domain between the most popular technologies in 2 1 st：biotechnology,nanotech and new materials， new energy resources，environment protection．By now,most scientists and researchers，high-tech corp．have invested large quantities of money,experiment apparatus，human beings into it to find materials with all of the premium properties： colossal dielectric constant,high resistance，low loss tangent，low—priced， low-sintering temperature，keeping steady in wide temperature and frequency range． Although，Several colossal dielectric materials have been reported by different authors， for example，CaCu3Ti4012，LuFe204，Lal5／8Srl／8N104，Li—and Ti-doped NiO．These materials have some flaws somewhere more less．For this reason，several physical mechanisms related to the outstanding dielectric phenomenon have been revealed to help improve the whole properties．That is，to have deep understanding of the interior physical law is of highly meaningful．By the way,some scientists ever reported that M2+Nb206(Ca，Nb，Ni，Mg，Zn)have good dielectric properties in microwave frequencies．Here，as a representation，M2+Nb206(Ca，Zn)ale studied in detail in the low-frequency range(under 10 Mnz)．Some interesting results follows： 1．CaNb206 ceramics exhibit intrinsic dielectric response with dielectric constant of 1 8．06 below 400 K．In the temperature range from 400 to 1 023 K， the sample successively shows relaxor-like peak and increasing ramp， which were having closely relationship with oxygen vacancies．Annealing treatment in N2 and 02 atmospheres revealed that the relaxor-like peak is consisted of two different relaxations(RI and R2)and the ramp is evidenced t0 be another relaxation(R3)．Our results demonstrated that the low-temperature relaxation(R 1)belongs to Maxwell-Wagner-type dielectric III 万方数据 铌酸盐材料的介电性能研究relaxation 铌酸盐材