Exchange-Biased NiFe_(2)O_(4)/NiO Nanocomposites Derived from NiFe-Layered Double Hydroxides as a Single Precursor  

作　　者：Xiaofei Zhao Sailong Xu Lianying Wang Xue Duan Fazhi Zhang 

机构地区：[1]State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology,Beijing 100029,China

出　　处：《Nano Research》2010年第3期200-210,共11页纳米研究（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China,the 111 Project(No.B07004);the 973 Program(No.2009CB939802);the Program for New Century Excellent Talents in Universities(No.NCET-07-0055);the Beijing Nova Program(No.2007B021).

摘　　要：NiFe_(2)O_(4) nanoparticles(<10 nm)embedded in a NiO matrix have been fabricated by calcining the corresponding Ni^(Ⅱ)Fe^(Ⅲ)-layered double hydroxide(LDH)precursors at high temperature(500℃).Compared with the NiFe_(2)O_(4)/NiO nanocomposite obtained by calcination of a precursor prepared by a traditional chemical coprecipitation method,those derived from NiFe-LDH precursors show much higher blocking temperatures(TB)(~380 K).The enhanced magnetic stability can be ascribed to the much stronger interfacial interaction between NiFe_(2)O_(4) and NiO phases due to the topotactic nature of the transformation of the LDH precursor to the NiFe_(2)O_(4)/NiO composite material.Through tuning the Ni^(Ⅱ)/Fe^(Ⅲ) molar ratio of the NiFe-LDH precursor,the NiFe_(2)O_(4) concentration can be precisely controlled,and the TB value as well as the magnetic properties of the final material can also be regulated.This work represents a successful example of the fabrication of ferro(ferri)magnetic(FM)/antiferrimagnetic(AFM)systems with high magnetic stability from LDH precursors.This method is general and may be readily extended to other FM/AFM systems due to the wide range of available LDH precursors.

关 键 词：Layered double hydroxide topotactic mechanism interfacial interaction exchange bias magnetic stability 

分 类 号：TB3[一般工业技术—材料科学与工程]