Batsaikhan Erdembayalag, Chen Yen-Cheng, Lee Chi-Hung, Li Hsiao-Chi, Li Wen-Hsien
Department of Physics, National Central University, Jhongli 32001, Taiwan.
Int J Mol Sci. 2015 Sep 24;16(10):23165-76. doi: 10.3390/ijms161023165.
We report on the results of investigating the ferromagnetic properties of bare Cu nanoparticles. Three sets of bare Cu nanoparticle assemblies with mean particle diameters of 6.6, 8.1, and 11.1 nm were fabricated, employing the gas condensation method. Curie-Weiss paramagnetic responses to a weak driving magnetic field were detected, showing the appearance of particle superspins that overcomes the diamagnetic responses from the inner core. The isothermal magnetization displays a Langevin field profile together with magnetic hysteresis appearing even at 300 K, demonstrating the existence of ferromagnetic superspins in the Cu nanoparticles. Shifting of a noticeable amount of electronic charge from being distributed near the lattice sites in bulk form toward their neighboring ions in nanoparticles was found. The extended 3d and 4s band mixture are the main sources for the development of localized 3d holes for the development of ferromagnetic particle superspins in Cu nanoparticles.
我们报告了对裸露铜纳米颗粒铁磁特性的研究结果。采用气体冷凝法制备了三组平均粒径分别为6.6、8.1和11.1纳米的裸露铜纳米颗粒组件。检测到对弱驱动磁场的居里-外斯顺磁响应，表明出现了克服内核抗磁响应的粒子超自旋。等温磁化呈现出朗之万场分布，即使在300 K时也出现磁滞现象，证明铜纳米颗粒中存在铁磁超自旋。发现有大量电子电荷从以体相形式分布在晶格位置附近向纳米颗粒中的相邻离子转移。扩展的3d和4s能带混合是铜纳米颗粒中形成用于铁磁粒子超自旋发展的局域3d空穴的主要来源。
