The effect of Eu3+ion doping in the La sites of single-crystal La4/3Sr5/3Mn2O7was investigated. Electron spin resonance(ESR) was applied to La4/3Sr5/3Mn2O7and(La0.8Eu0.2)4/3Sr5/3Mn2O7single crystals. A phase separatio...The effect of Eu3+ion doping in the La sites of single-crystal La4/3Sr5/3Mn2O7was investigated. Electron spin resonance(ESR) was applied to La4/3Sr5/3Mn2O7and(La0.8Eu0.2)4/3Sr5/3Mn2O7single crystals. A phase separation and phase transitions were observed from the ESR spectra data. Between 350 K and 300 K, both paramagnetic resonance(PMR)and anisotropic ferromagnetic resonance(FMR) lines were observed in the ab plane and the c axis direction, suggesting a coexistence of the paramagnetic(PM) phase and the ferromagnetic(FM) phase. The magnetization measurement reveals a spin-glass-like behavior in single-crystal(La0.8Eu0.2)4/3Sr5/3Mn2O7below the temperature of spin freezing Tf(～ 29.5 K).展开更多
The europium ions doped MMoO_4(M=Sr,Ba)nanophosphors were successfully synthesized via a facile hydrothermal method using isopropanol.The relationship between phosphor crystalline phase,morphology,photoluminescent pro...The europium ions doped MMoO_4(M=Sr,Ba)nanophosphors were successfully synthesized via a facile hydrothermal method using isopropanol.The relationship between phosphor crystalline phase,morphology,photoluminescent properties and hexadecyl trimethyl ammonium bromide(CTAB)concentration,pH value in precursor solution was investigated.The results indicated that the morphology and photoluminescent properties were strongly influenced by CTAB concentration and pH value in precursor solution.In SrMoO_4:Eu^(3+) hosts,the phosphor surface tended to become smoother as the concentration of CTAB was increased;while particles tended to agglomerate as increasing pH value.The relative intensity ratio of charge transfer band to Eu^(3+) characteristic emission peaks of MMoO_4:Eu^(3+)(M=Sr,Ba)was changed as CTAB concentration and pH value changed.The emission spectra of MMoO_4:Eu^(3+)(M=Sr,Ba)could be adjusted by CTAB concentration and pH value due to their impacts on the structure.It was important that the different morphologies and photoluminescent properties of MMoO_4:Eu^(3+)(M=Sr,Ba)could be obtained by the facile hydrothermal method and modulated by changing CTAB concentration and pH value.展开更多
Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of...Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of the γ-La2S3 phase to facilitate the nucleation process. The γ-La2S3 transformation occurred at significantly lower temperature by the combined contributions of low transformation enthalpy and induced multiple nuclei. On the other hand, the doped Eu ions could be inserted into the empty tetrahedral S4 cavities to stabilize the γ-La2S3 phase at temperature excess of 1100 ℃.展开更多
基金National Natural Science Foundation of China(51364024,50364002)Foundation of State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials(SKL 1316)Gansu Province Department of Education Fund(2013A-029)
基金supported by the National Natural Science Foundation of China(Grant Nos.11164019 and 11064008)the Inner Mongolia Natural ScienceFoundation,China(Grant Nos.NJZZ11166,NJZY10163,NJZY12202,2011MS0101,2011MS0108,and 2009MS0101)
文摘The effect of Eu3+ion doping in the La sites of single-crystal La4/3Sr5/3Mn2O7was investigated. Electron spin resonance(ESR) was applied to La4/3Sr5/3Mn2O7and(La0.8Eu0.2)4/3Sr5/3Mn2O7single crystals. A phase separation and phase transitions were observed from the ESR spectra data. Between 350 K and 300 K, both paramagnetic resonance(PMR)and anisotropic ferromagnetic resonance(FMR) lines were observed in the ab plane and the c axis direction, suggesting a coexistence of the paramagnetic(PM) phase and the ferromagnetic(FM) phase. The magnetization measurement reveals a spin-glass-like behavior in single-crystal(La0.8Eu0.2)4/3Sr5/3Mn2O7below the temperature of spin freezing Tf(～ 29.5 K).
基金Project supported by the Nation Natural Science Foundation of China(51562025)Graduate Student Innovation Special Funds(YC2016-S085)
文摘The europium ions doped MMoO_4(M=Sr,Ba)nanophosphors were successfully synthesized via a facile hydrothermal method using isopropanol.The relationship between phosphor crystalline phase,morphology,photoluminescent properties and hexadecyl trimethyl ammonium bromide(CTAB)concentration,pH value in precursor solution was investigated.The results indicated that the morphology and photoluminescent properties were strongly influenced by CTAB concentration and pH value in precursor solution.In SrMoO_4:Eu^(3+) hosts,the phosphor surface tended to become smoother as the concentration of CTAB was increased;while particles tended to agglomerate as increasing pH value.The relative intensity ratio of charge transfer band to Eu^(3+) characteristic emission peaks of MMoO_4:Eu^(3+)(M=Sr,Ba)was changed as CTAB concentration and pH value changed.The emission spectra of MMoO_4:Eu^(3+)(M=Sr,Ba)could be adjusted by CTAB concentration and pH value due to their impacts on the structure.It was important that the different morphologies and photoluminescent properties of MMoO_4:Eu^(3+)(M=Sr,Ba)could be obtained by the facile hydrothermal method and modulated by changing CTAB concentration and pH value.
基金supported by New Century Educational Talents Plan of Chinese Education Ministry, China (NCET-10-0171)the National Natural Sci-ence Foundation of China (60979003)the Fundamental Research Funds for the Central Universities (2009QN123)
文摘Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of the γ-La2S3 phase to facilitate the nucleation process. The γ-La2S3 transformation occurred at significantly lower temperature by the combined contributions of low transformation enthalpy and induced multiple nuclei. On the other hand, the doped Eu ions could be inserted into the empty tetrahedral S4 cavities to stabilize the γ-La2S3 phase at temperature excess of 1100 ℃.
