Polycrystalline samples of Sr5PrTi3Ta7O30 （SPTT） and Sr5EuTi3Ta7O30 （SETT） compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were stud...Polycrystalline samples of Sr5PrTi3Ta7O30 （SPTT） and Sr5EuTi3Ta7O30 （SETT） compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were studied. They are found to be ferroelectric phase of filled tetragonal tungsten bronze （TB） structure at room temperature and undergoes diffuse type of ferroelectric-paraelectric phase transition around 34 ℃ and 31 ℃, respectively. At 1 MHz SPTT exhibits high dielectric constants of 177 and low dielectric losses of 3.5×10^-4 and SETT has high dielectric constants of 125 and low dielectric losses of 2.4×10^-3.展开更多
The rapid development of capacitors with high energy density and efficiency has been driven by advanced electronic systems and innovative pulsed power applications.In this study,we prepared Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_...The rapid development of capacitors with high energy density and efficiency has been driven by advanced electronic systems and innovative pulsed power applications.In this study,we prepared Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=2.5,3,3.5,4,4.5)dielectric ceramics,which exhibited structural distortion due to the co-occupation of Ba^(2+),Sr^(2+),and Sm^(3+)in the A-site and the partial substitution of Nb^(5+)by Zr^(4+)in the B-site.The ordered/disordered distribution due to these distortions thus generated polar nanoregions(PNRs)and induced a relaxation ferroelectric behavior,which was verified by the high-resolution transmission electron microscopy.Through the use of the Vogel–Fulcher and Maxwell–Boltzmann equations,we found that easy inversion and small dipole sizes are crucial for achieving high energy storage density and efficiency.The Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)dielectric ceramic displayed a ferroelectric/paraelectric transition near room temperature.Subsequent ferroelectric testing revealed large energy storage density(Wrec=4.31 J·cm^(−3))and high efficiency(η=93.8%)at 310 kV·cm−1.Furthermore,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=4.5)exhibited higher breakdown field strength due to its large resistivity and small grain size.This led to energy storage density of approximately 5.3 J·cm^(−3)at 460 kV·cm^(−1).Additionally,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)demonstrated current density(CD)of approximately 713.38 A·cm^(−2)and power density(PD)of approximately 87.51 MW·cm^(−3),with ultrafast discharge time of 34 ns and excellent discharge energy density(Wdis)of approximately 2.27 J·cm^(−3).Overall,this study presents a promising approach for developing dielectric ceramic materials that hold potential for applications in innovative pulsed power components.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.50762002,50962004)the Project for New Century Excellent Talents in Guangxi (No.2006202) and ICDD Grant-in-Aid Program
文摘Polycrystalline samples of Sr5PrTi3Ta7O30 （SPTT） and Sr5EuTi3Ta7O30 （SETT） compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were studied. They are found to be ferroelectric phase of filled tetragonal tungsten bronze （TB） structure at room temperature and undergoes diffuse type of ferroelectric-paraelectric phase transition around 34 ℃ and 31 ℃, respectively. At 1 MHz SPTT exhibits high dielectric constants of 177 and low dielectric losses of 3.5×10^-4 and SETT has high dielectric constants of 125 and low dielectric losses of 2.4×10^-3.
基金the National Natural Science Foundation of China(No.12164012)the Science and Technology Major Project of Guangxi(No.AA21077012)for financial support.
文摘The rapid development of capacitors with high energy density and efficiency has been driven by advanced electronic systems and innovative pulsed power applications.In this study,we prepared Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=2.5,3,3.5,4,4.5)dielectric ceramics,which exhibited structural distortion due to the co-occupation of Ba^(2+),Sr^(2+),and Sm^(3+)in the A-site and the partial substitution of Nb^(5+)by Zr^(4+)in the B-site.The ordered/disordered distribution due to these distortions thus generated polar nanoregions(PNRs)and induced a relaxation ferroelectric behavior,which was verified by the high-resolution transmission electron microscopy.Through the use of the Vogel–Fulcher and Maxwell–Boltzmann equations,we found that easy inversion and small dipole sizes are crucial for achieving high energy storage density and efficiency.The Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)dielectric ceramic displayed a ferroelectric/paraelectric transition near room temperature.Subsequent ferroelectric testing revealed large energy storage density(Wrec=4.31 J·cm^(−3))and high efficiency(η=93.8%)at 310 kV·cm−1.Furthermore,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=4.5)exhibited higher breakdown field strength due to its large resistivity and small grain size.This led to energy storage density of approximately 5.3 J·cm^(−3)at 460 kV·cm^(−1).Additionally,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)demonstrated current density(CD)of approximately 713.38 A·cm^(−2)and power density(PD)of approximately 87.51 MW·cm^(−3),with ultrafast discharge time of 34 ns and excellent discharge energy density(Wdis)of approximately 2.27 J·cm^(−3).Overall,this study presents a promising approach for developing dielectric ceramic materials that hold potential for applications in innovative pulsed power components.
