Superspin-glass like behavior of nanoparticle La0.7Ca0.3MnO3 obtained by mechanochemical milling
Superspin-glass like behavior of nanoparticle La0.7Ca0.3MnO3 obtained by mechanochemical milling
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DOI：
10.1007/s11051-010-0076-2
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发表时间：
2011-02-01
影响因子：
2.5
通讯作者：
Blanusa, Jovan
中科院分区：
文献类型：
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作者：
Spasojevic, Vojislav;Mrakovic, Ana;Blanusa, Jovan
采用高能球磨法单步合成了单相钙钛矿化合物La0.7Ca0.3MnO3。结构和形貌表征表明该混合价锰矿具有纳米颗粒性质，平均粒径为9 nm。综合磁测量结果表明，该体系可以描述为一个相互作用的磁性纳米粒子系综，其中每个粒子都具有高磁矩，即超自旋。此外，超自旋玻璃态（SSG）和超顺磁态（SP）都对磁性行为有贡献，其主要性质取决于实验条件。结果表明，在500 Oe以下的低磁场中，SSG态占主导地位，而在较高的磁场中，纳米粒子的集体行为被抑制，个体特征占主导地位。结果表明，该方法制备的体系具有高磁各向异性和大的纳米粒子壳，其厚度可达颗粒直径的30%。
Single-phase perovskite compound La0.7Ca0.3MnO3 was synthesised by a high-energy ball milling in a single step processing. Structure and morphology characterizations revealed nanoparticle nature of this mixed valent manganite with the average particle diameter of 9 nm. Comprehensive set of magnetic measurements showed that the system can be described as an ensemble of interacting magnetic nanoparticles where each particle possesses high magnetic moment, i.e., superspin. Furthermore, magnetic behavior showed contributions from both superspin-glass (SSG) and superparamagnetic (SP) states, and the prevailing properties depended on the experimental conditions. It was established that SSG state dominated in low magnetic fields up to 500 Oe while in higher applied fields suppression of collective behavior occurred and individual characteristics of nanoparticles prevailed. It was also concluded that the applied method of synthesis produced system with high magnetic anisotropy as well as with the large nanoparticle shell whose thickness amounts 30% of a particle diameter.