Magnetic properties and magnetic domains of Nd–Fe–B thin films
Magnetic properties and magnetic domains of Nd–Fe–B thin films
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DOI：
10.1063/1.2836957
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发表时间：
2008-01
影响因子：
3.2
通讯作者：
Shuwen Chen;Wei Liu;Zhidong Zhang;G. Gunaratne
中科院分区：
文献类型：
--
作者：
Shuwen Chen;Wei Liu;Zhidong Zhang;G. Gunaratne
采用直流磁控溅射法在不同温度范围内的Si衬底上制备了各向异性Nd-Fe-B薄膜。用扫描探针显微镜观察了不同溅射温度（25-600 ℃）下制备的Nd-Fe-B薄膜的表面形貌和磁畴结构。磁畴具有丰富的织构，随着溅射温度的升高，磁畴从迷宫状变为云状。磁畴随衬底温度的变化进行了讨论，使用相成分和磁各向异性的薄膜。此外，磁畴的图案使用“无序函数”进行分析，这是一组具有无序结构的复杂图案的表征。无序函数δ（1）和结构因子δ k在衬底温度达到350 ℃之前没有明显变化，但在超过400 ℃时显著增加。随着溅射温度的升高，磁畴中的无序度增加。观察到薄膜的各向异性c织构和硬磁性能同时增强。在T（s）=400 ℃时无序函数的显著变化似乎是Nd-Fe-B膜硬化的前兆。衬底温度为600摄氏度时，薄膜的最无序磁畴对应于最佳磁性能，最大能积（BH）（max）为22.4 MG Oe。（C）2008美国物理研究所。
Anisotropic Nd-Fe-B thin films are fabricated by direct current magnetron sputtering on Si substrates heated to temperatures over a wide range. Surface morphology and magnetic domains of the Nd-Fe-B thin films prepared at different sputtering temperatures (25-600 degrees C) are observed by a scanning probe microscopy. The magnetic domains exhibit a rich variety of textures, changing from striped via maze to cloudlike as the sputtering temperature is increased. Variations in magnetic domains with substrate temperature are discussed using phase components and magnetic anisotropies of the thin films. In addition, patterns of magnetic domains are analyzed using the "disorder functions," a set of characterizations of complex patterns with labyrinthine structures. The disorder function delta(1) and the structure factor delta k do not change appreciably until a substrate temperature of 350 degrees C, but increases significantly beyond 400 degrees C. The disorder in magnetic domains increases with increasing sputtering temperature. A simultaneous enhancement of the anisotropic c texture and the hard-magnetic properties of the thin films are observed. The significant change of the disorder function at T(s)=400 degrees C appears to be a precursor to the hardening of the Nd-Fe-B film. The most disordered magnetic domains of the film with the substrate temperature of 600 degrees C correspond to the optimum magnetic properties, with the maximum energy product (BH)(max) of 22.4 MG Oe. (C) 2008 American Institute of Physics.