摘要
用聚乙二醇(PEG)和乙醇溶剂反沉淀法制备颗粒直径9.1~860nm的锂铁氧体纳米晶.X射线衍射分析表明这些纳米晶是纯LiFe5O8.用振动样品磁强计测量不同温度下的磁化和退化曲线,得出其比饱和磁化强度和矫顽力随纳米晶颗粒直径和温度的变化.利用趋近饱和定律求出不同温度下,样品的有效各向异性常数KE,发现颗粒直径为9.1nm的LiFe5O8纳米晶的KE比其大块材料的磁晶各向异性常数K1几乎增大10倍.利用均匀转动反磁化和混合矫顽力模型计算纳米晶的不同温度下的矫顽力。
Lithium ferrite (LiFe 5O 8) nanocrystallinte ranging from 9.1 ̄860 nm in size were prepared using PEG gel method. The nanocrystallite was identified to be pure lithium ferrite by means of X ray diffraction analysis. Their magnetization and demagnetization curves at different temperatures were measured using a vibrating sample magnetometer; the specific saturation magnetization and the coercivity change with the diameter of the nanocrystallinte and temperature have been obtained; the effective magnetic anisotropy constants K E of these samples were deduced using the law of approach to saturation. It is found that the K E value of lithium ferrite nanocrystallintes in 9.1 nm diameter is about ten times greater than the magnetocrystallinte anisotropy constant K 1 of bult lithium ferrite. The coercivities of the nanocrystallinte at different temperatures were calculated using the uniform rotation coercivity theory and the mixed coercivity theory. The calculated coercivity results are consistent with the experimental ones.
出处
《吉林大学自然科学学报》
CAS
CSCD
1998年第4期66-70,共5页
Acta Scientiarum Naturalium Universitatis Jilinensis
关键词
锂铁氧体
纳米晶
磁性
矫顽力
磁各向异性
lithium ferrite nanocrystallinte, magnetic properties, magnetic anisotropy, coercivity