Size-dependent magnetic properties and Raman spectra of La(2)NiMnO(6) nanoparticles

作者：Zhao Shuangyi; Shi Lei^*; Zhou Shiming; Zhao Jiyin; Yang Haipeng; Guo Yuqiao

来源：Journal of Applied Physics, 2009, 106(12): 123901.

DOI：10.1063/1.3269707

• Curie temperature
• Jahn-Teller effect
• lanthanum compounds
• magnetisation
• nanoparticles
• nanotechnology
• nickel compounds
• particle size
• Raman spectra
• sol-gel processing

The structure and magnetic properties of La(2)NiMnO(6) nanoparticles with sizes ranging from about 16 to 66 nm synthesized by a sol-gel method have been investigated. The magnetic measurements reveal that the rates of disordered phases increase as particle size decreases, which can be deduced from the changes of Curie temperature and the occurrence of glasslike behaviors, and the similar saturation magnetization was obtained at 4 K. While the particle size becomes smaller, two broad peaks of Raman spectrum at around 535 and 670 cm(-1), which are assigned to antisymmetric stretching mode and symmetric stretching mode, move to higher and lower frequencies than the corresponding modes of the bulk compound, respectively. The two peaks also become broader, while the intensity becomes relatively weaker with the decrease in nanoparticle size. All results support that the trend of Mn(4+)+Ni(2+)-> Mn(3+)+Ni(3+) bring locally cooperative Jahn-Teller deformation and charge disproportion, and demonstrate that the nanometer effect is a crucial factor to influence the properties of La(2)NiMnO(6).

• 出版日期2009-12-15
• 单位中国科学技术大学