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您的检索式：作者名="M.Siddique"
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| 1 | Concentration and Temperature Dependence of Electrical Conductivity in Thermally Stable Chromium Polyacrylate显示文摘Electrical conductivity of chromium polyacrylate with dopant concentration 30, 40 and 50 wt-% of chromium has been measured over a broad range of temperatures (303 K to 383 K).The electrical conductivity shows dependence on temperature, as well as, level of doping. The conductivity is considered to be due to thermal hopping motion of localized charge carriers,which are believed to be polarons, in the temperature range 303 K to 323 K and for T>343 K,whereas. it is metal-like in the temperature range 323 K to 343 | S. U.Rehman M.Siddique and Farid A.Khwaja(Materials Research Laboratory, Dept. of Physics, Quaid-i-Azam University, Islamabad, Pakistan)M.S.Zafar(Dept. of Physics, University of the Punjab, Lahore, Pakistan) | 1995 | Journal of Materials Science & Technology1995，11，6： | 2 |
| 2 | Effects of Ni doping on the structural properties and collapse of magnetic ordering in NdFe_(1-x)Ni_xO_3(0.1 ≤x≤ 0.7) orthoferrites显示文摘Nd Fe_(1-x)Ni_xO_3(0.1 ≤ x ≤ 0.7) orthoferrites are synthesized by solid state reaction method, and the structural properties of these materials are investigated by employing x-ray diffraction(XRD), scanning electron microscopy(SEM) and M o¨ssbauer spectroscopy. The orthorhombic structure is observed in all systems; however, with the increase in Ni doping,the increase in tolerance factor and the decrease in the cell volume are observed. Orthorhombic distortion decreases with Ni content increasing up to 50%, while above 50% Ni doping it increases. SEM examination indicates the increases in grain size and intermixing of grains with increase in Ni concentration. Comparison between bulk and theoretical densities shows that in each of all samples porosity is less than 2%. M?ssbauer spectroscopic investigations are performed to explain local structure, Fe oxidation states and collapse of the magnetic ordering. In these samples the Fe oxidation state remains+3 and there is no considerable increase in hole states observed; however due to mismatch of the ionic radii between Fe^(3+) and Ni^(3+), octahedral distortions, sagging and distribution of hyperfine parameters increase with increase in Ni concentration. The major factors behind the collapse of magnetic ordering in the Ni-doped systems are the weakening of the super-exchange interactions, decrease in the Neel temperature, increase in spin–spin relaxation frequency and high spin to low spin transition. | I.Ahmad M.J.Akhtar M.Siddique | 2016 | Chinese Physics B2016，25，2： | 0 |
| 3 | Mo,Ta和Ag温度因子的中子粉末衍射测量显示文摘固体的温度因子B由关系式Fobs=Feexp(-Bsin2θ/λ2)定义,其中Fobs和Fc分别为观测和计算的结构因子。由B可以直接得到两个重要的物理参数:晶格中原子热振动的均方振幅值〈U2〉和德拜温度Θ。 | 张百生 杨继廉 丁永凡 金兰 叶春堂 J.Bashir N.M.Butt M.Siddique M.Arshed Q.H.Khan | 1990 | 中国原子能科学研究院年报1990，，1： | 0 |
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