The effect of La^(3+),Mn^(2+)and Ni^(2+)doped calcium copper titanate,CaCu_(3)Ti_(4)O_(12)(CCTO),at higher concentrations(CR1 and CR2 with 5 mol%and 10 mol%,respectively),has been examined by semi-wet route at relativ...The effect of La^(3+),Mn^(2+)and Ni^(2+)doped calcium copper titanate,CaCu_(3)Ti_(4)O_(12)(CCTO),at higher concentrations(CR1 and CR2 with 5 mol%and 10 mol%,respectively),has been examined by semi-wet route at relatively lower temperature.This semi-wet route employs citrate-nitrate gel chemical method using TiO_(2) solid powders.X-ray diffraction(XRD)analysis confirms the formation of single phase in the doped samples sintered at 900℃for 8 h.Scanning electron micrographs(SEM)show that the average grain size for CR2 is larger than that of CR1 composition.The energy dispersive X-ray spectroscopy(EDX)is used to study the percentage compositions of different ions present in both ceramics.Dielectric constant(εr)and dielectric loss(tanδ)values of CR1 are comparatively higher than those of CR2 ceramic at all measured frequencies and temperatures.The nature of temperature-dependent relaxation behavior of the ceramics is also studied by impedance,modulus spectroscopic analysis and confirms Maxwell-Wagner relaxation.展开更多
Ultrafine powder of CaCu_(2.80)Zn_(0.20)Ti_(4)O_(12)ceramic was prepared using a novel semi-wet method.DTA/TG analysis of dry powder gives pre-information about formation offinal product around 800℃.The formation of ...Ultrafine powder of CaCu_(2.80)Zn_(0.20)Ti_(4)O_(12)ceramic was prepared using a novel semi-wet method.DTA/TG analysis of dry powder gives pre-information about formation offinal product around 800℃.The formation of single phase was confirmed by X-ray diffraction analysis.The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm,respectively.Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic.Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.展开更多
Yttrium Copper Titanate(Y_(2/3)Cu_(3)Ti_(4)O_(12))nanoceramic is structurally analogous to CaCu_(3)Ti_(4)O_(12)(CCTO).X-ray diffraction(XRD)of Y_(2/3)Cu_(3)Ti_(4)O_(12)(YCTO)shows the presence of all normal peaks of C...Yttrium Copper Titanate(Y_(2/3)Cu_(3)Ti_(4)O_(12))nanoceramic is structurally analogous to CaCu_(3)Ti_(4)O_(12)(CCTO).X-ray diffraction(XRD)of Y_(2/3)Cu_(3)Ti_(4)O_(12)(YCTO)shows the presence of all normal peaks of CCTO.SEM micrograph exhibits the presence of bimodal grains of size ranging from 1–2m.Bright field TEM image clearly displays nanocrystalline particle which is supported by presence of a few clear rings in the corresponding selected area electron diffraction(SAED)pattern.It exhibits a high value of dielectric constant("0?8434)at room temperature and 100 Hz frequency with characteristic relaxation peaks.Impedance and modulus studies revealed the presence of temperature-dependent Maxwell–Wagner type of relaxation in the ceramic.展开更多
文摘The effect of La^(3+),Mn^(2+)and Ni^(2+)doped calcium copper titanate,CaCu_(3)Ti_(4)O_(12)(CCTO),at higher concentrations(CR1 and CR2 with 5 mol%and 10 mol%,respectively),has been examined by semi-wet route at relatively lower temperature.This semi-wet route employs citrate-nitrate gel chemical method using TiO_(2) solid powders.X-ray diffraction(XRD)analysis confirms the formation of single phase in the doped samples sintered at 900℃for 8 h.Scanning electron micrographs(SEM)show that the average grain size for CR2 is larger than that of CR1 composition.The energy dispersive X-ray spectroscopy(EDX)is used to study the percentage compositions of different ions present in both ceramics.Dielectric constant(εr)and dielectric loss(tanδ)values of CR1 are comparatively higher than those of CR2 ceramic at all measured frequencies and temperatures.The nature of temperature-dependent relaxation behavior of the ceramics is also studied by impedance,modulus spectroscopic analysis and confirms Maxwell-Wagner relaxation.
文摘Ultrafine powder of CaCu_(2.80)Zn_(0.20)Ti_(4)O_(12)ceramic was prepared using a novel semi-wet method.DTA/TG analysis of dry powder gives pre-information about formation offinal product around 800℃.The formation of single phase was confirmed by X-ray diffraction analysis.The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm,respectively.Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic.Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.
文摘Yttrium Copper Titanate(Y_(2/3)Cu_(3)Ti_(4)O_(12))nanoceramic is structurally analogous to CaCu_(3)Ti_(4)O_(12)(CCTO).X-ray diffraction(XRD)of Y_(2/3)Cu_(3)Ti_(4)O_(12)(YCTO)shows the presence of all normal peaks of CCTO.SEM micrograph exhibits the presence of bimodal grains of size ranging from 1–2m.Bright field TEM image clearly displays nanocrystalline particle which is supported by presence of a few clear rings in the corresponding selected area electron diffraction(SAED)pattern.It exhibits a high value of dielectric constant("0?8434)at room temperature and 100 Hz frequency with characteristic relaxation peaks.Impedance and modulus studies revealed the presence of temperature-dependent Maxwell–Wagner type of relaxation in the ceramic.
