Theoretical studies of the cubic perovskite CaFeO3 are performed using the full potential linearized augmented plane-wave method with GGA+U.The calculated structural parameters are consistent with the experimental res...Theoretical studies of the cubic perovskite CaFeO3 are performed using the full potential linearized augmented plane-wave method with GGA+U.The calculated structural parameters are consistent with the experimental results.The tolerance factor reveals the cubic phase of the compound.The spin polarized electronic band structures and densities of states as well as the integer value of the magnetic moment of the unit cell(4μB)demonstrate that CaFeO_(3)is half metal.Ferromagnetism in CaFeO_(3)is due to Fe^(+4)–O^(2)–Fe^(+4)superexchange interaction.The robust properties of the compound show that with their compression up to a certain critical lattice constant,known as the robust transition lattice constant,an abrupt change in the electronic and magnetic properties occurs;the compounds lose their integer magnetic moment and become metallic.展开更多
The energy storage properties of (1-x)Bi_(0.5)Na_(0.5)TiO_(3-x)BaTiO_(3)(0≤x≤0.08)(BNT-BT)ceramics obtained via sol-gel method are determined from the polarization versus electric field(P-E)loops at various temperat...The energy storage properties of (1-x)Bi_(0.5)Na_(0.5)TiO_(3-x)BaTiO_(3)(0≤x≤0.08)(BNT-BT)ceramics obtained via sol-gel method are determined from the polarization versus electric field(P-E)loops at various temperatures.The energy storage densities are observed to increase with increase in temperature and this may be attributed to the presence of antiferroelectric(AFE)phase at higher temperature(≥120℃).Obvious changes are observed in the saturation polarization(P_(s)) and remnant polarization(P_(r)) with increasing temperature.The maximum energy storage density of 0.6 J/cm^(3)is observed for x=0:06 in the AFE phase at 150℃for 90 kV/cm of applied electric field.BNT-BT can be a promising candidate for energy storage devices to be used in above-roomtemperature environment.展开更多
文摘Theoretical studies of the cubic perovskite CaFeO3 are performed using the full potential linearized augmented plane-wave method with GGA+U.The calculated structural parameters are consistent with the experimental results.The tolerance factor reveals the cubic phase of the compound.The spin polarized electronic band structures and densities of states as well as the integer value of the magnetic moment of the unit cell(4μB)demonstrate that CaFeO_(3)is half metal.Ferromagnetism in CaFeO_(3)is due to Fe^(+4)–O^(2)–Fe^(+4)superexchange interaction.The robust properties of the compound show that with their compression up to a certain critical lattice constant,known as the robust transition lattice constant,an abrupt change in the electronic and magnetic properties occurs;the compounds lose their integer magnetic moment and become metallic.
基金This work was supported by the Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory,China.
文摘The energy storage properties of (1-x)Bi_(0.5)Na_(0.5)TiO_(3-x)BaTiO_(3)(0≤x≤0.08)(BNT-BT)ceramics obtained via sol-gel method are determined from the polarization versus electric field(P-E)loops at various temperatures.The energy storage densities are observed to increase with increase in temperature and this may be attributed to the presence of antiferroelectric(AFE)phase at higher temperature(≥120℃).Obvious changes are observed in the saturation polarization(P_(s)) and remnant polarization(P_(r)) with increasing temperature.The maximum energy storage density of 0.6 J/cm^(3)is observed for x=0:06 in the AFE phase at 150℃for 90 kV/cm of applied electric field.BNT-BT can be a promising candidate for energy storage devices to be used in above-roomtemperature environment.
