Strontium doped perovskite-type Nd0.7Sr0.3MnO3 ceramics were synthesized completely by high-energy ball milling raw oxides of Nd2O3, SrCO3 and MnO2. The optimal ball milling time and mass ratio of milling balls to raw...Strontium doped perovskite-type Nd0.7Sr0.3MnO3 ceramics were synthesized completely by high-energy ball milling raw oxides of Nd2O3, SrCO3 and MnO2. The optimal ball milling time and mass ratio of milling balls to raw materials are 4 h and 10：1, respectively. The grain size of as-milled Nd0.7Sr0.3MnO3 ceramics ranges from 51 to 93 nm, and the fine particles contain two phases of crystalline phase and amorphous phase. For the Nd0.7r0.3MnO3 synthesized by ball milling and sequent heat treatment, a remarkable colossal electroresistance （CER） effect is observed and the CER ratio reaches 900% at Curie temperature Tc when the load voltage increases from 0.1 to 0.8 V.展开更多
A kind of lead-free dielectric materials,such as the bismuth layered perovskite-type structure of Bi4-xTi3O12-1.5x(x=0.04,0.02,0,-0.02,-0.04),was prepared by the conventional solid-state method at 800C and sintered at...A kind of lead-free dielectric materials,such as the bismuth layered perovskite-type structure of Bi4-xTi3O12-1.5x(x=0.04,0.02,0,-0.02,-0.04),was prepared by the conventional solid-state method at 800C and sintered at 1100C.The variation of structure and electrical properties with different Bi concentration was studied.All the Bi4-xTi3O12-1.5x(x=0.04,0.02,0,-0.02,-0.04)samples exhibited a single structured phase.SEM could be a better approach to present the microstructure of Bi4-xTi3O12-1.5x(x=0.04,0.02,0,-0.02,-0.04)ceramics.It could be found that the grain size of Bi4.02Ti3O12.03 sintered at 1100C was smaller than that of others among the five samples through grain size mechanics.Through impedance spectra analysis,we knew,when the Bi content was fixed,that the dielectric constant and the loss values increased with the decrease of frequency.The Curie temperature of the five samples was about 670C.In particular,while at the frequency of 100 kHz,the lowest loss was 0.001 when Bi content was 3.98.The Bi4.02Ti3O12.03 ceramics with the minimum grain size had highest dielectric constant and the relatively low loss.Due to its high Curie temperature,high permittivity and low loss,the Bi_(4)Ti_(3)O_(12)(BIT)ceramics have a broad application prospect in high density memory,generator,sensor,ferroelectric tunnel junctions and so on.展开更多
基金the National Natural Science Foundation of China (Grant No.10774040) and the joint Chinese-Russian Project for their financial supports
文摘Strontium doped perovskite-type Nd0.7Sr0.3MnO3 ceramics were synthesized completely by high-energy ball milling raw oxides of Nd2O3, SrCO3 and MnO2. The optimal ball milling time and mass ratio of milling balls to raw materials are 4 h and 10：1, respectively. The grain size of as-milled Nd0.7Sr0.3MnO3 ceramics ranges from 51 to 93 nm, and the fine particles contain two phases of crystalline phase and amorphous phase. For the Nd0.7r0.3MnO3 synthesized by ball milling and sequent heat treatment, a remarkable colossal electroresistance （CER） effect is observed and the CER ratio reaches 900% at Curie temperature Tc when the load voltage increases from 0.1 to 0.8 V.
基金funding provided by the National Natural Science Foundation of China(Grant No.51202063).
文摘A kind of lead-free dielectric materials,such as the bismuth layered perovskite-type structure of Bi4-xTi3O12-1.5x(x=0.04,0.02,0,-0.02,-0.04),was prepared by the conventional solid-state method at 800C and sintered at 1100C.The variation of structure and electrical properties with different Bi concentration was studied.All the Bi4-xTi3O12-1.5x(x=0.04,0.02,0,-0.02,-0.04)samples exhibited a single structured phase.SEM could be a better approach to present the microstructure of Bi4-xTi3O12-1.5x(x=0.04,0.02,0,-0.02,-0.04)ceramics.It could be found that the grain size of Bi4.02Ti3O12.03 sintered at 1100C was smaller than that of others among the five samples through grain size mechanics.Through impedance spectra analysis,we knew,when the Bi content was fixed,that the dielectric constant and the loss values increased with the decrease of frequency.The Curie temperature of the five samples was about 670C.In particular,while at the frequency of 100 kHz,the lowest loss was 0.001 when Bi content was 3.98.The Bi4.02Ti3O12.03 ceramics with the minimum grain size had highest dielectric constant and the relatively low loss.Due to its high Curie temperature,high permittivity and low loss,the Bi_(4)Ti_(3)O_(12)(BIT)ceramics have a broad application prospect in high density memory,generator,sensor,ferroelectric tunnel junctions and so on.
