Ceramic samples of(1-x)BiFeO_(3)-xPbFe_(0.5)Sb_(0.5)O_(3)(BFO-xPFS),(1-x)BiFeO_(3)-xSrFe_(0.5) Sb_(0.5)O_(3)(BFO-xSFS)where(x=0.05,0.1,..,0.9),(1-x)BiFeO_(3)-xBaFe_(0.5)Nb_(0.5)O_(3)(BFO-xBFN)and(1-x)BiFeO_(3)-xSrFe_(...Ceramic samples of(1-x)BiFeO_(3)-xPbFe_(0.5)Sb_(0.5)O_(3)(BFO-xPFS),(1-x)BiFeO_(3)-xSrFe_(0.5) Sb_(0.5)O_(3)(BFO-xSFS)where(x=0.05,0.1,..,0.9),(1-x)BiFeO_(3)-xBaFe_(0.5)Nb_(0.5)O_(3)(BFO-xBFN)and(1-x)BiFeO_(3)-xSrFe_(0.5)Nb_(0.5)O_(3)(BFO-xSFN)where(x=0,0.01,0.02,..,0.1,0.2,...,1)solid solutions with a perovskite structure were obtained.Mossbauer studies have shown that the Neel temperature T_(N) concentration dependences of the systems studied are in good agreement with T_(N)(x)calculated under the assumption of the ordered distribution of Fe^(3+)and nonmagnetic Sb^(5+)ions in the lattice.The T_(N) values obtained for BFO-xBFN and BFO-xPFS are close to the values,calculated for cases of the disordered and ordered distribution of Fe^(3+)and nonmagnetic Nb^(5+)and Sb^(5+)ions in the latice,respectively.The T_(N) values of BFO-xSFN and BFO-xSFS are in the range between the calculated values for ordered and disordered cases.Moreover the anomaly on the T_(N)(x)dependence for the BFO-xBFN and BFO-xSFN systems was found near x=0.7.This anomaly is most likely related to the destruction of the magnetic super exchange via the empty 6p state of Bi^(3+)ions.展开更多
synthesisCeramic samples of BiFeO_(3)-based perovskite solid solutions with the highly ordered complex perovskites PbFe_(1/2)Sb_(1/2)O_(3)(PFS)and SrFe_(1/2)Sb_(1/2)O_(3)(SFS)were obtained using high-pressure synthesi...synthesisCeramic samples of BiFeO_(3)-based perovskite solid solutions with the highly ordered complex perovskites PbFe_(1/2)Sb_(1/2)O_(3)(PFS)and SrFe_(1/2)Sb_(1/2)O_(3)(SFS)were obtained using high-pressure synthesis at 4-6 GPa.Mössbauer studies revealed that BiFeO_(3)-SFS compositions are characterized by a larger compositional inhomogeneity as compared to BiFeO_(3)-PFS ones.In line with this result,concentration dependence of the magnetic phase transition temperature TN for BiFeO_(3)-SFS compositions is close to the TN(x)dependence for BiFeO_(3)solid solution with disordered perovskite PbFe_(1/2)Nb_(1/2)O_(3)(PFN).In contrast to this TN(x)dependence for BiFeO_(3)-PFS compositions nicely follows the theoretical TN(x)dependence calculated for the case of the ordered distribution of Fe3+and non-magnetic Sb^(5)+ions in the lattice(chemical ordering).展开更多
0.5AFeO_(3)-0.5NaNbO_(3)(A=Bi,La)solid solution compositions were prepared using a solid phase reaction route from high-purity starting oxides.Mossbauer studies have shown that while for 0.5BiFeO_(3)-0.5NaNbO_(3)the m...0.5AFeO_(3)-0.5NaNbO_(3)(A=Bi,La)solid solution compositions were prepared using a solid phase reaction route from high-purity starting oxides.Mossbauer studies have shown that while for 0.5BiFeO_(3)-0.5NaNbO_(3)the magnetic phase transition temperature T_(M) value is about 150 K,for 0.5LaFeO_(3)-0.5NaNbO_(3),it is only≈25 K.This dramatic difference in T_(M) values seems to be due to additional contribution of the magnetic superexchange between Fe^(3+)ions via the empty 6p-states of Bi^(3+)ions to the overall superexchange.展开更多
In the present work,the comparative study of the electric response of Sn_(2)P_(2)S_(6) films to the visible light action was carried out without and under external electric field.The light flux modulated by a chopper ...In the present work,the comparative study of the electric response of Sn_(2)P_(2)S_(6) films to the visible light action was carried out without and under external electric field.The light flux modulated by a chopper induces the integral response comprising time-dependent photoelectric and photovoltaic components.It was shown that spontaneous polarization influences the electric response characteristics.展开更多
基金supported by the Russian Science Foundation(Grant No.23-42-10024)the Belarusian Republican Foundationfor Fundamental Researches(Grant No.T23RNF-086).
文摘Ceramic samples of(1-x)BiFeO_(3)-xPbFe_(0.5)Sb_(0.5)O_(3)(BFO-xPFS),(1-x)BiFeO_(3)-xSrFe_(0.5) Sb_(0.5)O_(3)(BFO-xSFS)where(x=0.05,0.1,..,0.9),(1-x)BiFeO_(3)-xBaFe_(0.5)Nb_(0.5)O_(3)(BFO-xBFN)and(1-x)BiFeO_(3)-xSrFe_(0.5)Nb_(0.5)O_(3)(BFO-xSFN)where(x=0,0.01,0.02,..,0.1,0.2,...,1)solid solutions with a perovskite structure were obtained.Mossbauer studies have shown that the Neel temperature T_(N) concentration dependences of the systems studied are in good agreement with T_(N)(x)calculated under the assumption of the ordered distribution of Fe^(3+)and nonmagnetic Sb^(5+)ions in the lattice.The T_(N) values obtained for BFO-xBFN and BFO-xPFS are close to the values,calculated for cases of the disordered and ordered distribution of Fe^(3+)and nonmagnetic Nb^(5+)and Sb^(5+)ions in the latice,respectively.The T_(N) values of BFO-xSFN and BFO-xSFS are in the range between the calculated values for ordered and disordered cases.Moreover the anomaly on the T_(N)(x)dependence for the BFO-xBFN and BFO-xSFN systems was found near x=0.7.This anomaly is most likely related to the destruction of the magnetic super exchange via the empty 6p state of Bi^(3+)ions.
基金The reported study was funded by RFBR(Project number 20-52-00045)BRFBR(Project number T20R-169).
文摘synthesisCeramic samples of BiFeO_(3)-based perovskite solid solutions with the highly ordered complex perovskites PbFe_(1/2)Sb_(1/2)O_(3)(PFS)and SrFe_(1/2)Sb_(1/2)O_(3)(SFS)were obtained using high-pressure synthesis at 4-6 GPa.Mössbauer studies revealed that BiFeO_(3)-SFS compositions are characterized by a larger compositional inhomogeneity as compared to BiFeO_(3)-PFS ones.In line with this result,concentration dependence of the magnetic phase transition temperature TN for BiFeO_(3)-SFS compositions is close to the TN(x)dependence for BiFeO_(3)solid solution with disordered perovskite PbFe_(1/2)Nb_(1/2)O_(3)(PFN).In contrast to this TN(x)dependence for BiFeO_(3)-PFS compositions nicely follows the theoretical TN(x)dependence calculated for the case of the ordered distribution of Fe3+and non-magnetic Sb^(5)+ions in the lattice(chemical ordering).
基金This work was supported by RFBR and NSFC,project 19-52-53030 GFEN a and by the Ministry of Education and Science of the Russian Federation(State assignment in the field of scientific activity,Southern Federal University,2020).
文摘0.5AFeO_(3)-0.5NaNbO_(3)(A=Bi,La)solid solution compositions were prepared using a solid phase reaction route from high-purity starting oxides.Mossbauer studies have shown that while for 0.5BiFeO_(3)-0.5NaNbO_(3)the magnetic phase transition temperature T_(M) value is about 150 K,for 0.5LaFeO_(3)-0.5NaNbO_(3),it is only≈25 K.This dramatic difference in T_(M) values seems to be due to additional contribution of the magnetic superexchange between Fe^(3+)ions via the empty 6p-states of Bi^(3+)ions to the overall superexchange.
基金This work was supported by Russian Science Foundation(Grant No.15-19-00138).
文摘In the present work,the comparative study of the electric response of Sn_(2)P_(2)S_(6) films to the visible light action was carried out without and under external electric field.The light flux modulated by a chopper induces the integral response comprising time-dependent photoelectric and photovoltaic components.It was shown that spontaneous polarization influences the electric response characteristics.
