Influence of Sr doping on structural, electrical and magnetic properties of La0.7Ca0.3MnO3 nanoparticles
Influence of Sr doping on structural, electrical and magnetic properties of La0.7Ca0.3MnO3 nanoparticles
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Sr掺杂对La0.7Ca0.3MnO3纳米颗粒结构、电学和磁学性能的影响
DOI：
10.1016/j.ceramint.2017.07.021
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发表时间：
2017
影响因子：
5.2
通讯作者：
Liu Xiang
中科院分区：
文献类型：
--
作者：
Zhao Shuang;Yue Xue-Jiao;Liu Xiang
Abstract La 0.7 Ca 0.3 MnO 3 nanoparticles doped with Sr (La 0.7 (Ca 0.3-x Sr x) MnO 3, x= 0, 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30) were prepared by sol–gel method. Their structural, electrical and magnetic properties were examined by various analytical methods. XRD (X-ray diffraction) showed a transition in phase from orthorhombic (space group of Pbnm) to rhombohedral (space group of R 3 ̅ c) at x= 0.10∼ 0.15. Cell volume continuously expanded as x increased due to larger radius of Sr 2+ ion (1.31 Å) compared to that of Ca 2+(1.18 Å). This substitution accordingly led to changes in tolerance factor (τ). TEM images confirmed structural phase transition from Pbnm to R 3 ̅ c. Average particle sizes of samples with x= 0.05 and 0.25 were measured by TEM as 56 nm and 45 nm, respectively. Furthermore, a significant increase in T c and T p for LCSMO nanoparticles was observed as x rose from lower to higher values. The enhancement of double− exchange (DE) interactions was caused by larger radius of Sr 2+ cation, which induced modifications in the Mn− O− Mn bond angles and Mn− O bond distance. This, in turn, boosted magnetic and electrical properties of the resulting nanoparticles. On the other hand, the effect of particle size and intrinsic characteristics was found responsible for approximate values of saturation magnetization. Finally, the increase in coercivity and the decrease in temperature coefficient of resistance (TCR%) were related to spin disordered surface layers of particles and scattering of electrons at grain boundaries, respectively.
