Microstructure and magnetic characteristics of nanocrystalline Ni0.5Zn0.5 ferrite synthesized by a spraying-coprecipitation method

• 来源期刊: 中国物理B（英文版）
• 关键词: nanocrystalline material Ni0.5Zn0.5 ferrite spraying-coprecipitation method,magnetic properties
• 年，卷（期）: 2007,（12）
• 页码范围: 3837-3842
• 页数: 6页
• 语种: 英文

摘要

Nanocrystalline Ni0.5Zn0.5 ferrite with average grain sizes ranging from 10 to 100 nm is prepared by using a spraying-coprecipitation method. The results indicate that the nanocrystalline Ni0.5Zn0.5 ferrite is ferromagnetic without the superparamagnetic phenomenon observed at room temperature. Specific saturation magnetization of nanocrystalline Ni0.5Zn0.5 ferrite increases from 40.2 to 75.6 emu/g as grain size increases from 11 to 94nm. Coercivity of nanocrystalline Ni0.5Zn0.5 ferrite increases monotonically when d ＜ 62 nm. The relationship between the coercivity and the mean grain size is well fitted into a relation Hc ～ d3. A theoretically evaluated value of the critical grain size is 141nm larger than the experimental value 62nm for nanocrystalline Ni0.5Zn0.5 ferrite. The magnetic behaviour of nanocrystalline Ni0.5Zn0.5 ferrite may be explained by using the random anisotropy theory.