The exchange interaction between the electrons in the different magnetic ions and the spin-fluctuation of the magnetic ions exist in the paramagnetic media NdF3. The exchange interaction between the electrons in the d...The exchange interaction between the electrons in the different magnetic ions and the spin-fluctuation of the magnetic ions exist in the paramagnetic media NdF3. The exchange interaction between the electrons in the different magnetic ions may be equivalent to an effective field Hin that is in direct proportion to the magnetization M. The spin-fluctuation of the magnetic ions leads the coefficient of the effective field to vary with temperature. The effective field is given as Hin = -（0.75 ＋ 0.22T） × 10^-5M in NdF3. When the secondary crystal field effect is taken into account, the magnetic susceptibility and Verdet constant are calculated for NdF3 by means of the effective field Hin and the applied field He. The calculated results are in agreement with the measured ones.展开更多
This paper reports that a series of Nd3＋：Er3＋：yb3＋ co-doped borosilicate glasses have been prepared and their absorption spectra measured. The J-O intensity parameters Ωk （k = 2, 4, 6）, spontaneous radiative l...This paper reports that a series of Nd3＋：Er3＋：yb3＋ co-doped borosilicate glasses have been prepared and their absorption spectra measured. The J-O intensity parameters Ωk （k = 2, 4, 6）, spontaneous radiative lifetime Trad, spontaneous transition probability A, fluorescence branching ratio β and oscillator strength fed of the Nd3＋ ions at room temperature are calculated based on Judd-Ofelt （J-O） theory. The temperature dependence of the up-conversion photoluminescence characteristics in a Nd3＋：Er3＋：Yb3＋ co-doped sample is studied under a 978 nm semiconductor laser excitation, and the energy transfer mechanisms among Yb3＋, Er3＋ and Nd3＋ ions are analysed. The results show that the J-O intensity parameters Ω2 increase when the Nd3＋ concentration of the Nd3＋：Er3＋：yb3＋ co-doped borosilicate glasses increases. The possibility of spontaneous transition is small and lifetimes are long at levels of 4F5/2 and 4F3/2. The intensity of Nd3＋ emissions at 595, 691, 753, 813 and 887 nm axe markedly enhanced when the sample temperature exceeds 400 K. The reasons being the cooperation of the secondary sensitization from Era＋ to Nd3＋ and the contribution of a multi-phonon.展开更多
Based on the temperature dependence of spin fluctuations of magnetic ions,the exchange field Hexch acting on the rare-earth ions in Pr-substituted yttrium iron garnet(Pr:YIG)is modified,which is expressed as H_(exch)=...Based on the temperature dependence of spin fluctuations of magnetic ions,the exchange field Hexch acting on the rare-earth ions in Pr-substituted yttrium iron garnet(Pr:YIG)is modified,which is expressed as H_(exch)=n0(1+γT+βe^(ωT))MYIG.By means of the improved exchange field,the magnetic and magneto-optical properties of Pr:YIG are calculated.The calculated results are in good agreement with the experimental data in the temperature range of 4.2–300 K.Our study implies that the spin fluctuations of magnetic ions have an important influence on the magnetic and magneto-optical properties of Pr:YIG at low temperature.展开更多
基金Project supported by the Science and Technology Foundation of China University of Mining and Technology (Grant No OK061066)
文摘The exchange interaction between the electrons in the different magnetic ions and the spin-fluctuation of the magnetic ions exist in the paramagnetic media NdF3. The exchange interaction between the electrons in the different magnetic ions may be equivalent to an effective field Hin that is in direct proportion to the magnetization M. The spin-fluctuation of the magnetic ions leads the coefficient of the effective field to vary with temperature. The effective field is given as Hin = -（0.75 ＋ 0.22T） × 10^-5M in NdF3. When the secondary crystal field effect is taken into account, the magnetic susceptibility and Verdet constant are calculated for NdF3 by means of the effective field Hin and the applied field He. The calculated results are in agreement with the measured ones.
基金Project supported by the Fundamental Research Funds for the Central Universities(Grant No.2010LKWL07)the National Basic Research Program of China(Grant No.2010CB226805)
文摘This paper reports that a series of Nd3＋：Er3＋：yb3＋ co-doped borosilicate glasses have been prepared and their absorption spectra measured. The J-O intensity parameters Ωk （k = 2, 4, 6）, spontaneous radiative lifetime Trad, spontaneous transition probability A, fluorescence branching ratio β and oscillator strength fed of the Nd3＋ ions at room temperature are calculated based on Judd-Ofelt （J-O） theory. The temperature dependence of the up-conversion photoluminescence characteristics in a Nd3＋：Er3＋：Yb3＋ co-doped sample is studied under a 978 nm semiconductor laser excitation, and the energy transfer mechanisms among Yb3＋, Er3＋ and Nd3＋ ions are analysed. The results show that the J-O intensity parameters Ω2 increase when the Nd3＋ concentration of the Nd3＋：Er3＋：yb3＋ co-doped borosilicate glasses increases. The possibility of spontaneous transition is small and lifetimes are long at levels of 4F5/2 and 4F3/2. The intensity of Nd3＋ emissions at 595, 691, 753, 813 and 887 nm axe markedly enhanced when the sample temperature exceeds 400 K. The reasons being the cooperation of the secondary sensitization from Era＋ to Nd3＋ and the contribution of a multi-phonon.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No JK126046.
文摘Based on the temperature dependence of spin fluctuations of magnetic ions,the exchange field Hexch acting on the rare-earth ions in Pr-substituted yttrium iron garnet(Pr:YIG)is modified,which is expressed as H_(exch)=n0(1+γT+βe^(ωT))MYIG.By means of the improved exchange field,the magnetic and magneto-optical properties of Pr:YIG are calculated.The calculated results are in good agreement with the experimental data in the temperature range of 4.2–300 K.Our study implies that the spin fluctuations of magnetic ions have an important influence on the magnetic and magneto-optical properties of Pr:YIG at low temperature.
