摘要
采用熔体快淬方法制备的[(Fe_(1-x)Co_x)_(0.675)Pt_(0.325)]_(84)B_(16)(X=0.1～0.5)系列纳米晶甩带,通过优化退火热处理后,运用磁力/原子力显微镜(MFM/AFM)研究了Co浓度对样品的晶体与微磁结构的影响.结果表明,甩带的微磁及微晶结构与Co对Fe替代的浓度密切相关.甩带的微磁结构可确定为交换耦合畴结构,由随机分布的黑白相间的点状畴构成,且畴的尺寸约为3～6个其晶粒尺寸的大小.运用Landau-Lifshitz自由能最小化理论解释了纳必晶甩带形成交换耦合畴的机理.甩带的微晶颗粒的直径随着Co含量的增加而变化,但都小于100 nm.具有高矫顽力(_iH_e)样品呈现了更一致、更大的磁畴结构和更均匀、更细小的晶粒结构.平均的畴尺寸与晶粒尺寸的比例(ω/D)可以半定量地表征交换耦合的强度,当x=0.3时ω/D达到最大值,此时交换耦合最强,这与磁性测量的结果完全一致.
Effect of Co contents on magnetic and crystalline microstructures was investigated, by using the melt - spun [（Fe1-xCox）0.675Pt0.325]84B16（ x = 0.1 - 0.5 ） nanocomposite ribbons after optimal thermal treatment, and using magnetic force microscopy （MFM）. The results indicate that the magnetic and crystalline microstructures are closely interrelated with Co substitution concentration. The magnetic microstructures, identified as exchange - coupling domains, are characterized by darker and brighter spots in random distribution with the sizes of as large as those of 3 - 6 grains. The formation of the exchange - coupling domains is expounded based on the minimization theory of Landau- Lifshitz free energy. The microcrystalline grains in the ribbons are less than 100 nm, varying with Co contents. The ribbons with higher coercivity （iHc） have more uniform and larger domains as well as more homogeneous and the smaller grains. The ration of the domain width to grain size （w/D） might represent the interaction strength of the exchange coupling semi - quantitatively. When the w/D reaches maximum at x = 0.3 the coupling is strongest, which agrees with the results of magnetic measurements.
出处
《湖南科技大学学报（自然科学版）》
CAS
北大核心
2012年第4期112-116,共5页
Journal of Hunan University of Science And Technology：Natural Science Edition
基金
湖南省科技厅国际合作项目(2012WK3022)
国家自然科学基金项目(NSFC11104067)
