It is theoretically investigated the generation of higher harmonics of two-dimensional and three-dimensional terahertz electromagnetic beams in nonlinear crystals. The attention is paid to crystalline paraelectrics li...It is theoretically investigated the generation of higher harmonics of two-dimensional and three-dimensional terahertz electromagnetic beams in nonlinear crystals. The attention is paid to crystalline paraelectrics like SrTiO<sub>3</sub> under the temperatures 60 - 200 K, these crystals possess the cubic nonlinearity. The bias electric field is applied to provide the dominating quadratic nonlinearity. The initial focusing of the beams not only increases the efficiency of generation of higher harmonics, but alto makes possible to select maxima of different higher harmonics at some distances from the input. At lower temperatures the nonlinearity behaves at smaller input amplitudes, whereas at higher temperatures the harmonic generation can be observed at higher frequencies up to 1.5 THz. In three-dimensional beams the peak amplitudes of higher harmonics can be bigger than in two-dimensional beams, but the ratios of these peak values to the maximum values of the focused first harmonic are smaller than in two-dimensional beams.展开更多
The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO<sub>3</sub> at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias...The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO<sub>3</sub> at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias electric field the dominating nonlinearity is cubic. The frequency dispersion and nonlinearity correspond to existence of envelope solitons and the modulation instability (MI) of long input pulses, whereas in the transverse direction MI is absent. There exists a possibility to generate the regular sequences of short THz pulses due to MI in bounded SrTiO<sub>3</sub> crystals. The focusing of input long pulses reduces the threshold of MI, increases the output amplitudes of the short pulses, and provides more stable generation of the short pulses. It is investigated the frequency multiplication of THz electromagnetic radiation in bounded paraelectric SrTiO<sub>3</sub> when a bias electric field is applied. The dominating nonlinearity is quadratic there. The frequency dispersion and the transverse width of the input wave beams affect the generation of higher harmonics. It is possible to select the certain numbers of higher harmonics by means of the optimum length of the crystal, by the width of the beam of the input first harmonic, and by the focusing of the input first harmonic.展开更多
Polycrystalline Sr5LnTi3Ta7O30 （Ln=La, Nd, Sm and Y） ceramics were prepared as single-phase materials through conventional solid-state ceramics method. The structure was characterized by X-ray diffraction method and...Polycrystalline Sr5LnTi3Ta7O30 （Ln=La, Nd, Sm and Y） ceramics were prepared as single-phase materials through conventional solid-state ceramics method. The structure was characterized by X-ray diffraction method and scanning electron microscopy （SEM）. The dielectric properties were measured from room temperature to 400℃. All compounds are paraelectric phases adopting the filled tetragonal tungsten bronze （TB） structure at room temperature. At 1 MHz their dielectric constant （ετ） varied from 109 to 139, dielectric loss changed from 0.003 3 to 0.005 8, and the temperature coefficients of the dielectric constant （τε） moved from -710 to -880×10^-6℃^-1.展开更多
With the increasing impacts of climate change and resource depletion,dielectric capacitors,with their exceptional stability,fast charging and discharging rates,and ability to operate under more extreme conditions,are ...With the increasing impacts of climate change and resource depletion,dielectric capacitors,with their exceptional stability,fast charging and discharging rates,and ability to operate under more extreme conditions,are emerging as promising high-demand candidates for high-performance energy storage devices,distinguishing them from traditional electrochemical capacitors and batteries.However,due to the shortcomings of various dielectric ceramics(e.g.,paraelectrics(PEs),ferroelectrics(FEs),and antiferroelectrics(AFEs)),their low polarizability,low breakdown strength(BDS),and large hysteresis loss limit their standalone use in the advancement of energy storage ceramics.Therefore,synthesizing novel perovskite-based materials that exhibit high energy density,high energy efficiency,and low loss is crucial for achieving superior energy storage performance.In this review,we outline the recent development of perovskitebased ferroelectric energy storage ceramics from the perspective of combinatorial optimization for tailoring ferroelectric hysteresis loops and comprehensively discuss the properties arising from the different combinations of components.We also provide future guidelines in this realm.Therefore,the combinatorial optimization strategy in this review will open up a practical route toward the application of new high-performance ferroelectric energy storage devices.展开更多
AgNbO_(3)(AN)and modified AgNbO_(3) have been extensively investigated as promising lead-free antiferroelectric(AFE)energy storage materials.Previous studies have focused mainly on the use of an ion dopant at the A/B ...AgNbO_(3)(AN)and modified AgNbO_(3) have been extensively investigated as promising lead-free antiferroelectric(AFE)energy storage materials.Previous studies have focused mainly on the use of an ion dopant at the A/B site to obtain a stabilized AFE phase;however,simultaneous improvements in the recoverable energy storage density(Wrec)and efficiency(n)are stll difficult to realize.Herein,we innovatively constructed a AgNbO_(3)-NaNbO_(3)-(Sr_(0.7)Bi_(0.2))TiO_(3)(AN-NN-SBT)ternary solid solution to achieve a relaxor AFE in AgNbO_(3)-based materials.The coexistence of antiferroelectric(M3)and paraelectric(O)phases in 0.8(0.7AgNbO_(3)-0.3NaNbO_(3))-0.2(Sro.7Bio.2)TiO_(3) confirms the successful realization of a relaxor AFE,attributed to multiple ion occupation at the A/B sites.Consequently,a high Wrec of 7.53 J.cm^(-3) and n of 74.0% are acquired,together with superior stability against various temperatures,frequencies,and cycling numbers.Furthermore,a high power density(298.7 MW·cm^(-3))and fast discharge speed(41.4 ns)are also demonstrated for the AgNbO_(3)-based relaxor AFE.This work presents a promising energy storage AgNbO_(3)-based ternary solid solution and proposes a novel strategy for AgNbO_(3)-based energy storage via the design of relaxor AFE materials.展开更多
The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage den...The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage density and efficiency. Herein, good energy storage properties were realized in (1-x)NaNbO_(3)- xNaTaO_(3) ceramics, by building a new phase boundary. As a result, a high recoverable energy density(Wrec) of 2.2 J/cm3 and efficiency (h) of 80.1% were achieved in 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic at300 kV/cm. The excellent energy storage performance originates from an antiferroelectric-paraelectricphase boundary with simultaneously high polarization and low hysteresis, by tailoring the ratio ofantiferroelectric and paraelectric phases. Moreover, the 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic also exhibitedgood temperature and frequency stability, together with excellent charge-discharge performance. Theresults pave a good way of designing new NaNbO_(3)-based antiferroelectrics with good energy storageperformance.展开更多
Inorganic relaxor ferroelectric solid solution single crystals are spurring new generations of high performance electromechanical devices,including transducers,sensors,and actuators,due to their ultrahigh electric fie...Inorganic relaxor ferroelectric solid solution single crystals are spurring new generations of high performance electromechanical devices,including transducers,sensors,and actuators,due to their ultrahigh electric field induced strain,large piezoelectric constant,high electromechanical coupling factor and low dielectric loss.However,relaxor ferroelectric single crystals found in organic-inorganic hybrid perovskites are very limited,but achieving these superior properties in them will be of great significance in the design of modern functional materials.Fortunately,here the first two-dimensional(2D)organic-inorganic hybrid relaxor ferroelectric single crystal,[Br(CH_(2))_(3)NH_(3)]_(2)PbBr_(4)(BPA_(2)-PbBr_(4),BPA=3-bromopropylamine),achieves some of superior properties.Interestingly,BPA_(2)-PbBr_(4)reveals a successive relaxor ferroelectric-ferroelectric-paraelectric phase transitions accompanying by a large degree of relaxationΔT_(relax)=61 K and ultralow energy loss(tanδ<0.001).Meanwhile,it exhibits a superior second harmonic generation(SHG)effect with maximum value accounts for 95%of the standard KDP due to great deformation of structure(3.2302×10^(-4)).In addition,temperature dependent luminescence spectra(80-415 K)exhibit fluorescence and phosphorescence overlapping emission originated from inorganic and organic components with the nanosecond-scale short lifetime and the millisecond-scale long lifetime,respectively,and the color of the emitted light is continuously adjustable,which is the first to achieve luminescence and relaxor ferroelectricity compatibility.展开更多
Multiferroic materials with coexisting ferroelectric and magnetic orders have attracted tremendous research interests because of their intriguing fundamental physics as well as potential applications in the next-gener...Multiferroic materials with coexisting ferroelectric and magnetic orders have attracted tremendous research interests because of their intriguing fundamental physics as well as potential applications in the next-generation multifunctional devices. Hexaferrites with conical magnetic structures are among the most promising single-phase multiferroics because strong magnetoelectric effects can be achieved in them from low temperatures up to room temperature in low magnetic fields. In this review, after briefly introducing the background on multiferroics and classification of hexaferrites, we summarize recent progress in multiferroic hexaferrites, including the mechanisms of spin-induced ferroelectricity, the magnetoelectric phase diagram, giant direct and converse magnetoelectric effects. Furthermore, we present a new mechanism of magnetic-ion-induced displacive polarization in hexaferrites, which leads to quantum paraelectricity and quantum electric-dipole liquid in M-type hexaferrites.展开更多
A new quantum spin liquid(QSL)candidate material H3LiIr2O6 was synthesized recently and was found not to show any magnetic order or phase transition down to low temperatures.In this work,we study the quantum dynamics ...A new quantum spin liquid(QSL)candidate material H3LiIr2O6 was synthesized recently and was found not to show any magnetic order or phase transition down to low temperatures.In this work,we study the quantum dynamics of the hydrogen ions,i.e.,protons,in this material by combining first-principles calculations and theoretical analysis.We show that each proton and its adjacent oxygen ions form an electric dipole.The dipole interactions and the proton tunneling are captured by a transverse-field Ising model with a quantum disordered paraelectric ground state.The dipole excitations have an energy gap△d=60 meV,and can be probed by the infrared optical spectroscopy and the dielectric response.We argue that the electric dipole fluctuations renormalize the magnetic interactions in H3LiIr2O6 and lead to a Kitaev QSL state.展开更多
文摘It is theoretically investigated the generation of higher harmonics of two-dimensional and three-dimensional terahertz electromagnetic beams in nonlinear crystals. The attention is paid to crystalline paraelectrics like SrTiO<sub>3</sub> under the temperatures 60 - 200 K, these crystals possess the cubic nonlinearity. The bias electric field is applied to provide the dominating quadratic nonlinearity. The initial focusing of the beams not only increases the efficiency of generation of higher harmonics, but alto makes possible to select maxima of different higher harmonics at some distances from the input. At lower temperatures the nonlinearity behaves at smaller input amplitudes, whereas at higher temperatures the harmonic generation can be observed at higher frequencies up to 1.5 THz. In three-dimensional beams the peak amplitudes of higher harmonics can be bigger than in two-dimensional beams, but the ratios of these peak values to the maximum values of the focused first harmonic are smaller than in two-dimensional beams.
文摘The nonlinear waves of terahertz (THz) range are investigated in the paraelectric crystals SrTiO<sub>3</sub> at the temperatures ~77 K. The frequency dispersion is important there. In the absence of a bias electric field the dominating nonlinearity is cubic. The frequency dispersion and nonlinearity correspond to existence of envelope solitons and the modulation instability (MI) of long input pulses, whereas in the transverse direction MI is absent. There exists a possibility to generate the regular sequences of short THz pulses due to MI in bounded SrTiO<sub>3</sub> crystals. The focusing of input long pulses reduces the threshold of MI, increases the output amplitudes of the short pulses, and provides more stable generation of the short pulses. It is investigated the frequency multiplication of THz electromagnetic radiation in bounded paraelectric SrTiO<sub>3</sub> when a bias electric field is applied. The dominating nonlinearity is quadratic there. The frequency dispersion and the transverse width of the input wave beams affect the generation of higher harmonics. It is possible to select the certain numbers of higher harmonics by means of the optimum length of the crystal, by the width of the beam of the input first harmonic, and by the focusing of the input first harmonic.
文摘Polycrystalline Sr5LnTi3Ta7O30 （Ln=La, Nd, Sm and Y） ceramics were prepared as single-phase materials through conventional solid-state ceramics method. The structure was characterized by X-ray diffraction method and scanning electron microscopy （SEM）. The dielectric properties were measured from room temperature to 400℃. All compounds are paraelectric phases adopting the filled tetragonal tungsten bronze （TB） structure at room temperature. At 1 MHz their dielectric constant （ετ） varied from 109 to 139, dielectric loss changed from 0.003 3 to 0.005 8, and the temperature coefficients of the dielectric constant （τε） moved from -710 to -880×10^-6℃^-1.
基金support from the National Natural Science Foundation of China(No.52202154)support from the Highperformance Computing Platform of China Agricultural University.
文摘With the increasing impacts of climate change and resource depletion,dielectric capacitors,with their exceptional stability,fast charging and discharging rates,and ability to operate under more extreme conditions,are emerging as promising high-demand candidates for high-performance energy storage devices,distinguishing them from traditional electrochemical capacitors and batteries.However,due to the shortcomings of various dielectric ceramics(e.g.,paraelectrics(PEs),ferroelectrics(FEs),and antiferroelectrics(AFEs)),their low polarizability,low breakdown strength(BDS),and large hysteresis loss limit their standalone use in the advancement of energy storage ceramics.Therefore,synthesizing novel perovskite-based materials that exhibit high energy density,high energy efficiency,and low loss is crucial for achieving superior energy storage performance.In this review,we outline the recent development of perovskitebased ferroelectric energy storage ceramics from the perspective of combinatorial optimization for tailoring ferroelectric hysteresis loops and comprehensively discuss the properties arising from the different combinations of components.We also provide future guidelines in this realm.Therefore,the combinatorial optimization strategy in this review will open up a practical route toward the application of new high-performance ferroelectric energy storage devices.
基金This work was supported by the National Natural Science Foundation of China(Nos.12204503 and U2002217)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-3-1-18)+2 种基金the Shanghai Pujiang Program(No.22PJD085)the Natural Science Foundation of Shanghai(No.23ZR1472400)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(No.YESS20210265).
文摘AgNbO_(3)(AN)and modified AgNbO_(3) have been extensively investigated as promising lead-free antiferroelectric(AFE)energy storage materials.Previous studies have focused mainly on the use of an ion dopant at the A/B site to obtain a stabilized AFE phase;however,simultaneous improvements in the recoverable energy storage density(Wrec)and efficiency(n)are stll difficult to realize.Herein,we innovatively constructed a AgNbO_(3)-NaNbO_(3)-(Sr_(0.7)Bi_(0.2))TiO_(3)(AN-NN-SBT)ternary solid solution to achieve a relaxor AFE in AgNbO_(3)-based materials.The coexistence of antiferroelectric(M3)and paraelectric(O)phases in 0.8(0.7AgNbO_(3)-0.3NaNbO_(3))-0.2(Sro.7Bio.2)TiO_(3) confirms the successful realization of a relaxor AFE,attributed to multiple ion occupation at the A/B sites.Consequently,a high Wrec of 7.53 J.cm^(-3) and n of 74.0% are acquired,together with superior stability against various temperatures,frequencies,and cycling numbers.Furthermore,a high power density(298.7 MW·cm^(-3))and fast discharge speed(41.4 ns)are also demonstrated for the AgNbO_(3)-based relaxor AFE.This work presents a promising energy storage AgNbO_(3)-based ternary solid solution and proposes a novel strategy for AgNbO_(3)-based energy storage via the design of relaxor AFE materials.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.11864004 and 52072080)The author also thanks to the fund(Grant No.20KF-16)from the Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education/Guangxi Key Laboratory of Optical and Electronic Materials and Devices,Guilin University of Technology,Guilin(541004),China.
文摘The NaNbO_(3) antiferroelectrics have been considered as a potential candidate for dielectric capacitorsapplications. However, the high-electric-field-unstable antiferroelectric phase resulted in low energystorage density and efficiency. Herein, good energy storage properties were realized in (1-x)NaNbO_(3)- xNaTaO_(3) ceramics, by building a new phase boundary. As a result, a high recoverable energy density(Wrec) of 2.2 J/cm3 and efficiency (h) of 80.1% were achieved in 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic at300 kV/cm. The excellent energy storage performance originates from an antiferroelectric-paraelectricphase boundary with simultaneously high polarization and low hysteresis, by tailoring the ratio ofantiferroelectric and paraelectric phases. Moreover, the 0.50NaNbO_(3)-0.50NaTaO_(3) ceramic also exhibitedgood temperature and frequency stability, together with excellent charge-discharge performance. Theresults pave a good way of designing new NaNbO_(3)-based antiferroelectrics with good energy storageperformance.
基金supported by the National Natural Science Foundation of China(22001102,21788102)the Jiangxi Provincial Natural Science Foundation(20202BAB213002)+2 种基金the Education Department of Jiangxi Province(GJJ190474)the Fundamental Research Funds for the Central Universities(JXUST,205200100116)the Program for Excellent Young Talents(JXUST,JXUSTQJYX2020018)。
文摘Inorganic relaxor ferroelectric solid solution single crystals are spurring new generations of high performance electromechanical devices,including transducers,sensors,and actuators,due to their ultrahigh electric field induced strain,large piezoelectric constant,high electromechanical coupling factor and low dielectric loss.However,relaxor ferroelectric single crystals found in organic-inorganic hybrid perovskites are very limited,but achieving these superior properties in them will be of great significance in the design of modern functional materials.Fortunately,here the first two-dimensional(2D)organic-inorganic hybrid relaxor ferroelectric single crystal,[Br(CH_(2))_(3)NH_(3)]_(2)PbBr_(4)(BPA_(2)-PbBr_(4),BPA=3-bromopropylamine),achieves some of superior properties.Interestingly,BPA_(2)-PbBr_(4)reveals a successive relaxor ferroelectric-ferroelectric-paraelectric phase transitions accompanying by a large degree of relaxationΔT_(relax)=61 K and ultralow energy loss(tanδ<0.001).Meanwhile,it exhibits a superior second harmonic generation(SHG)effect with maximum value accounts for 95%of the standard KDP due to great deformation of structure(3.2302×10^(-4)).In addition,temperature dependent luminescence spectra(80-415 K)exhibit fluorescence and phosphorescence overlapping emission originated from inorganic and organic components with the nanosecond-scale short lifetime and the millisecond-scale long lifetime,respectively,and the color of the emitted light is continuously adjustable,which is the first to achieve luminescence and relaxor ferroelectricity compatibility.
基金supported by the National Natural Science Foundation of China(Grant Nos.11534015,and 51725104)the National Key Research and Development Program of China(Grant No.2016YFA0300701)
文摘Multiferroic materials with coexisting ferroelectric and magnetic orders have attracted tremendous research interests because of their intriguing fundamental physics as well as potential applications in the next-generation multifunctional devices. Hexaferrites with conical magnetic structures are among the most promising single-phase multiferroics because strong magnetoelectric effects can be achieved in them from low temperatures up to room temperature in low magnetic fields. In this review, after briefly introducing the background on multiferroics and classification of hexaferrites, we summarize recent progress in multiferroic hexaferrites, including the mechanisms of spin-induced ferroelectricity, the magnetoelectric phase diagram, giant direct and converse magnetoelectric effects. Furthermore, we present a new mechanism of magnetic-ion-induced displacive polarization in hexaferrites, which leads to quantum paraelectricity and quantum electric-dipole liquid in M-type hexaferrites.
基金supported by the National Key Basic Research Program of China(Grant No.2014CB920902)the National Key Research and Development Program of China(Grant Nos.2017YFA0302904,and 2018YFA0305800)+2 种基金the National Natural Science Foundation of China(Grant No.11804337)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)the Beijing Municipal Science&Technology Commission(Grant No.Z181100004218001)。
文摘A new quantum spin liquid(QSL)candidate material H3LiIr2O6 was synthesized recently and was found not to show any magnetic order or phase transition down to low temperatures.In this work,we study the quantum dynamics of the hydrogen ions,i.e.,protons,in this material by combining first-principles calculations and theoretical analysis.We show that each proton and its adjacent oxygen ions form an electric dipole.The dipole interactions and the proton tunneling are captured by a transverse-field Ising model with a quantum disordered paraelectric ground state.The dipole excitations have an energy gap△d=60 meV,and can be probed by the infrared optical spectroscopy and the dielectric response.We argue that the electric dipole fluctuations renormalize the magnetic interactions in H3LiIr2O6 and lead to a Kitaev QSL state.
