Several samples of manganese oxides La(1-x)2/3Ca1/3MnO3 (V-LCMO) and (La0.7-xY0.3)2/3Ca1/3MnO3 (x<0.15) (V-LYCMO) with vacancies at La-site (La-vacancy) were prepared by solid-state reaction method. The X-ray diffr...Several samples of manganese oxides La(1-x)2/3Ca1/3MnO3 (V-LCMO) and (La0.7-xY0.3)2/3Ca1/3MnO3 (x<0.15) (V-LYCMO) with vacancies at La-site (La-vacancy) were prepared by solid-state reaction method. The X-ray diffraction(XRD) patterns refined by Rietveld confirm that these compounds exhibit single phase structure with orthorhombic symmetry (Pnma). The lattice parameters, Mn—O bond length and Mn—O—Mn bond angle vary with La-vacancy concentration, as an indication of the occurrence of the local Jahn-Teller effect. The measurement result of V-LCMO compounds shows that the maximum magnetoresistance(MR) is about 220% at TIM=268 K and La-vacancy content x=0.04. For V-LYCMO compounds, there exists metal-insulator transition at about 50 K, and a very large MR (over 106%) is observed at the temperature ranging from 40 K to 50 K.展开更多
To modify the shape difference between the spherical vacancy and the realistic vacancy, a shape factor is introduced into Brooks’ vacancy model. It is shown that the modified model is more efficient in predicting the...To modify the shape difference between the spherical vacancy and the realistic vacancy, a shape factor is introduced into Brooks’ vacancy model. It is shown that the modified model is more efficient in predicting the vacancy volume of metals than the original one, and the calculated vacancy volumes of 17 metals by the modified model agree with the values reported in literatures. Furthermore, the present results show that the vacancy shape may contribute 2%-9% to the whole vacancy volume.展开更多
SY508-3-69[篇名]Annealing effect on the recovery of training effect in FeO { sub } x/CoFe polycryst alline systems，SY508-3-70[篇名]Characterization of the metastable austenite in low-alloy FeCMnSi TRIP-aided steel by...SY508-3-69[篇名]Annealing effect on the recovery of training effect in FeO { sub } x/CoFe polycryst alline systems，SY508-3-70[篇名]Characterization of the metastable austenite in low-alloy FeCMnSi TRIP-aided steel by neutron diffraction，……展开更多
基金Project(0150014) supported by the Natural Science Foundation of Jiangxi Province, China
文摘Several samples of manganese oxides La(1-x)2/3Ca1/3MnO3 (V-LCMO) and (La0.7-xY0.3)2/3Ca1/3MnO3 (x<0.15) (V-LYCMO) with vacancies at La-site (La-vacancy) were prepared by solid-state reaction method. The X-ray diffraction(XRD) patterns refined by Rietveld confirm that these compounds exhibit single phase structure with orthorhombic symmetry (Pnma). The lattice parameters, Mn—O bond length and Mn—O—Mn bond angle vary with La-vacancy concentration, as an indication of the occurrence of the local Jahn-Teller effect. The measurement result of V-LCMO compounds shows that the maximum magnetoresistance(MR) is about 220% at TIM=268 K and La-vacancy content x=0.04. For V-LYCMO compounds, there exists metal-insulator transition at about 50 K, and a very large MR (over 106%) is observed at the temperature ranging from 40 K to 50 K.
基金the National Natural Science Foundation of China(No.50401010).
文摘To modify the shape difference between the spherical vacancy and the realistic vacancy, a shape factor is introduced into Brooks’ vacancy model. It is shown that the modified model is more efficient in predicting the vacancy volume of metals than the original one, and the calculated vacancy volumes of 17 metals by the modified model agree with the values reported in literatures. Furthermore, the present results show that the vacancy shape may contribute 2%-9% to the whole vacancy volume.
文摘SY508-3-69[篇名]Annealing effect on the recovery of training effect in FeO { sub } x/CoFe polycryst alline systems，SY508-3-70[篇名]Characterization of the metastable austenite in low-alloy FeCMnSi TRIP-aided steel by neutron diffraction，……
