Phase diagrams of the RE （rare earth）-Ⅳ-Ⅵ systems are very important for the design of rare earth doped diluted magnetic semiconductors （DMSs）, but related information is very limited. In this work, the phase eq...Phase diagrams of the RE （rare earth）-Ⅳ-Ⅵ systems are very important for the design of rare earth doped diluted magnetic semiconductors （DMSs）, but related information is very limited. In this work, the phase equilibria of the Er-Sn-Te system in whole compositional range at room temperature were investigated mainly by means of X-ray powder diffraction （XRD） and differential thermal analysis （DTA）. The existences of 9 binary compounds, i.e., SnTe, ErTe3, EraTe3, ErTe, ErsSn3, Er11Sn10, ErSn2, Er3Sn7 and Er2Sn5 were confirmed. The phase diagram consisted of 12 single-phase regions, 21 binary phase regions and 10 ternary phase re- gions. The maximum solid solubility of Er in SnTe was determined to be about 7.5 at.%, none of the other phases in this system re- vealed a remarkable homogeneity range at room temperature. No ternary compound was found in this work.展开更多
Single-phase diluted magnetic systems Zn1-xFexO have been prepared by chemical route. Structural and spectroscopic （UV-Vis and Mossbauer） studies indicate the incorporation of Fe^3＋ ions in the lattice sites. The U...Single-phase diluted magnetic systems Zn1-xFexO have been prepared by chemical route. Structural and spectroscopic （UV-Vis and Mossbauer） studies indicate the incorporation of Fe^3＋ ions in the lattice sites. The UV-Vis results point to a systematic increase in the band gap with increasing Fe doping. The room temperature magnetization of Zni-xFexO indicates a paramagnetic behavior which is in accordance with the Mossbauer results, illustrating quadrupolar doublet. At low temperature, the zero-field-cooled （ZFC） magnetization shows a cusp and this temperature increases systematically with decreasing particle size. The weak exchange bias effect manifested by a M-H loop shift is observed for x = 0.03. This shift is accompanied by the enhancement of coercivity. The dc magnetization results suggest the coexis tence of ferromagnetic and antiferromagnetic exchange interactions for low doping of Fe, i.e., for x = 0.03.展开更多
The phase boundary relationship for site-bond percolation is established by generalizingthe universal relationships in pure bond percolation and pure site percolation, and the phasetransition in diluted magnetic syste...The phase boundary relationship for site-bond percolation is established by generalizingthe universal relationships in pure bond percolation and pure site percolation, and the phasetransition in diluted magnetic system is studied. By using the Potts model, the phase bound-ary relationship for ferromagnetic-paramagnetic and antiferromagnetic-paramagnetic transi-tions is derived. The method adopted in this paper is convenient, simple and accurate.Especially, it has a clearer physical meaning.展开更多
基金supported by the Guangxi Science and Technology Development Project (11107003-1)National Natural Science Foundation of China (50601006, 51161002)
文摘Phase diagrams of the RE （rare earth）-Ⅳ-Ⅵ systems are very important for the design of rare earth doped diluted magnetic semiconductors （DMSs）, but related information is very limited. In this work, the phase equilibria of the Er-Sn-Te system in whole compositional range at room temperature were investigated mainly by means of X-ray powder diffraction （XRD） and differential thermal analysis （DTA）. The existences of 9 binary compounds, i.e., SnTe, ErTe3, EraTe3, ErTe, ErsSn3, Er11Sn10, ErSn2, Er3Sn7 and Er2Sn5 were confirmed. The phase diagram consisted of 12 single-phase regions, 21 binary phase regions and 10 ternary phase re- gions. The maximum solid solubility of Er in SnTe was determined to be about 7.5 at.%, none of the other phases in this system re- vealed a remarkable homogeneity range at room temperature. No ternary compound was found in this work.
文摘Single-phase diluted magnetic systems Zn1-xFexO have been prepared by chemical route. Structural and spectroscopic （UV-Vis and Mossbauer） studies indicate the incorporation of Fe^3＋ ions in the lattice sites. The UV-Vis results point to a systematic increase in the band gap with increasing Fe doping. The room temperature magnetization of Zni-xFexO indicates a paramagnetic behavior which is in accordance with the Mossbauer results, illustrating quadrupolar doublet. At low temperature, the zero-field-cooled （ZFC） magnetization shows a cusp and this temperature increases systematically with decreasing particle size. The weak exchange bias effect manifested by a M-H loop shift is observed for x = 0.03. This shift is accompanied by the enhancement of coercivity. The dc magnetization results suggest the coexis tence of ferromagnetic and antiferromagnetic exchange interactions for low doping of Fe, i.e., for x = 0.03.
文摘The phase boundary relationship for site-bond percolation is established by generalizingthe universal relationships in pure bond percolation and pure site percolation, and the phasetransition in diluted magnetic system is studied. By using the Potts model, the phase bound-ary relationship for ferromagnetic-paramagnetic and antiferromagnetic-paramagnetic transi-tions is derived. The method adopted in this paper is convenient, simple and accurate.Especially, it has a clearer physical meaning.
