کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1595829 | 1515725 | 2006 | 5 صفحه PDF | دانلود رایگان |
The effect of Pr doping on structural properties and room temperature Raman spectroscopy measurements is investigated in manganites (Eu1−xPrx)0.6Sr0.4MnO3 (0≤x≤1.0) with fixed carrier concentration. The result of the Rietveld refinement of x-ray powder diffraction shows that these compounds crystallize in an orthorhombic distorted structure with a space group Pnma. It is evident that, with increasing Pr substitution, three types of orthorhombic structures can be distinguished. The phonon frequencies of the three main peaks, in room temperature Raman-scattering measurements, have been discussed together with their structural characteristics, such as bond-length, bond-angles, and the change of orthorhombic structure type. With the increase of Pr content, the mode at 491 cm−1 also shows a corresponding change. A step effect becomes evident, which seems to indicate the close dependence between the frequency shift of this mode and the change in crystal symmetry. This further supports the notion that the mode at 491 cm−1 is closely correlated with the Jahn–Teller distortion. Moreover, we have found that the lowest frequency peak (assigned as an A1g phonon mode) depends linearly on the tolerance factor tt.
Journal: Solid State Communications - Volume 140, Issues 11–12, December 2006, Pages 503–507