We examine the validity of nonlinear thermodynamic models which incorporate the contribution of electrostatic coupling and interfacial space charge in ferroelectric-paraelectric bilayers.Inconsistency of the direction...We examine the validity of nonlinear thermodynamic models which incorporate the contribution of electrostatic coupling and interfacial space charge in ferroelectric-paraelectric bilayers.Inconsistency of the directions between build-in polarization and field is found.Evolution of ferroelectricity does not follow the variation in coupling strength between different layers.In addition,we observe that the field-induced polarization in the paraelectric layer deviates from the polarization derived by thermodynamic theory.These findings indicate that the current versions of thermodynamic models need to be modified.展开更多
Structural characteristics of phase transition in single-domain epitaxial BiFeO_(3)films are studied by the Landau–Devonshire theory.It is predicted that remanent polarization shows strong strain dependence for diffe...Structural characteristics of phase transition in single-domain epitaxial BiFeO_(3)films are studied by the Landau–Devonshire theory.It is predicted that remanent polarization shows strong strain dependence for different temperatures while spontaneous polarization is almost independent of strain over a wide temperature(0–500°C).We also obtain the thickness dependence of the c−axis lattice parameter and Curie temperature,and make a comparison between the polarization rotation angle and the angle attributed to the structural evolution in epitaxial(001)p BiFeO_(3)films grown on SrTiO_(3)substrates.The theoretical results are in agreement with recent experimental and theoretical data.Our calculations show that the clamping effect should also be taken into account in order to depict the mechanism of the polarization rotation completely.展开更多
Correlated fission fragments from the reaction of 25MeV/u ^(40)Ar+^(209)Bi and their further correlation with a par-tides have been studied for peripheral and central collisions simultaneously.The excitation energy at...Correlated fission fragments from the reaction of 25MeV/u ^(40)Ar+^(209)Bi and their further correlation with a par-tides have been studied for peripheral and central collisions simultaneously.The excitation energy at scission deduced from postscission multiplicity is about 1725 MeV.The fission timescale deduced from prescission multiplicity is about 4×10^(21)s.Systematic analysis of the mass and energy distributions of Hssion fragments as a function of the initial temperature of hot fissioning nuclei reveals the existence of different fission behavior of hot nuclei formed in central and peripheral collisions.Experimental data demonstrate the change of Hssion behavior at T~4MeV.展开更多
基金Supported by the Major Project of Gansu Provincial Science and Technology Department(1102GKDD035).
文摘We examine the validity of nonlinear thermodynamic models which incorporate the contribution of electrostatic coupling and interfacial space charge in ferroelectric-paraelectric bilayers.Inconsistency of the directions between build-in polarization and field is found.Evolution of ferroelectricity does not follow the variation in coupling strength between different layers.In addition,we observe that the field-induced polarization in the paraelectric layer deviates from the polarization derived by thermodynamic theory.These findings indicate that the current versions of thermodynamic models need to be modified.
基金the National Innovation Experiment Program for University Students(101073029).
文摘Structural characteristics of phase transition in single-domain epitaxial BiFeO_(3)films are studied by the Landau–Devonshire theory.It is predicted that remanent polarization shows strong strain dependence for different temperatures while spontaneous polarization is almost independent of strain over a wide temperature(0–500°C).We also obtain the thickness dependence of the c−axis lattice parameter and Curie temperature,and make a comparison between the polarization rotation angle and the angle attributed to the structural evolution in epitaxial(001)p BiFeO_(3)films grown on SrTiO_(3)substrates.The theoretical results are in agreement with recent experimental and theoretical data.Our calculations show that the clamping effect should also be taken into account in order to depict the mechanism of the polarization rotation completely.
基金Supported by the National Natural Science Foundation of China under Grant No.19235011.
文摘Correlated fission fragments from the reaction of 25MeV/u ^(40)Ar+^(209)Bi and their further correlation with a par-tides have been studied for peripheral and central collisions simultaneously.The excitation energy at scission deduced from postscission multiplicity is about 1725 MeV.The fission timescale deduced from prescission multiplicity is about 4×10^(21)s.Systematic analysis of the mass and energy distributions of Hssion fragments as a function of the initial temperature of hot fissioning nuclei reveals the existence of different fission behavior of hot nuclei formed in central and peripheral collisions.Experimental data demonstrate the change of Hssion behavior at T~4MeV.
