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| Co50Fe50-xSix合金的结构相变和磁性 | |
| 引用本文： | 赵晶晶,舒迪,祁欣,刘恩克,朱伟,冯琳,王文洪,吴光恒. Co50Fe50-xSix合金的结构相变和磁性[J]. 物理学报, 2011, 60(10): 107203-555 |
| 作者姓名： | 赵晶晶 舒迪 祁欣 刘恩克 朱伟 冯琳 王文洪 吴光恒 |
| 作者单位： | 1. 北京化工大学理学院,北京100029／中国科学院物理研究所磁学国家重点实验室,北京100190 2. 北京化工大学理学院,北京,100029 3. 中国科学院物理研究所磁学国家重点实验室,北京,100190 |
| 基金项目： | 国家重点基础研究发展计划(批准号:2010CB833102)、国家自然科学基金(批准号:60971019)和北京市教育委员会学科与研究生教育建设项目专项资助的课题. |
| 摘 要： | 利用实验测量和理论计算相结合的方法,研究了介于B2结构CoFe低有序合金和L21结构Co2FeSi高有序合金之间的Co50Fe50-xSix合金的结构相变、磁相变、分子磁矩和居里温度.采用考虑Coulomb相互作用的广义梯度近似（GGA＋U）方法计算了合金的能带结构.研究发现,合金出现较强的原子有序倾向,表现出较强的共价成相作用.合金的晶格常数、磁矩、居里温度随Si含量的增加而线性地降低,极限成分Co2FeSi合金的分子磁矩和居里温度分别达到5.92μB和777℃.原子尺寸效应导致合金晶格发生变化,但并未成为居里温度和分子磁矩变化的主导因素.分子磁矩的变化符合Slater-Pauling原理,但发现原子磁矩的变化并非线性,据此提出了共价成相对磁性影响的观点.采用Stearns理论解释了居里温度的变化趋势,排除了原子间距对居里温度的主导影响作用.能带计算的结果还表明,Co2FeSi作为半金属材料并非十分完美,可能在实际应用中会出现自旋极化率降低的问题.发现该系列合金的结构相变和磁相变随着成分的变化聚集在窄小的成分和温度范围内. |
| 关 键 词： | 磁性 Heusler合金 结构相变 |
Structural phase transition and magnetic properties of Co50Fe50-xSix alloys |
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| Zhao Jing-Jing,Shu Di,Qi Xin,Liu En-Ke,Zhu Wei,Feng Lin,Wang Wen-Hong and Wu Guang-Heng. Structural phase transition and magnetic properties of Co50Fe50-xSix alloys[J]. Acta Physica Sinica, 2011, 60(10): 107203-555 | |
| Authors: | Zhao Jing-Jing Shu Di Qi Xin Liu En-Ke Zhu Wei Feng Lin Wang Wen-Hong Wu Guang-Heng |
| Affiliation: | School of Science, Beijing University of Chemical Technology, Beijing 100029, China;State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;School of Science, Beijing University of Chemical Technology, Beijing 100029, China;School of Science, Beijing University of Chemical Technology, Beijing 100029, China;State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China |
| Abstract: | The structural and the magnetic properties of Co50Fe50-xSix alloys are investigated by carrying out experimental measurements and electron structure calculation.The alloy series exhibits the highly chemical ordering structure,showing a strong covalent bonding effect.The lattice parameters,molecular moment and Curie temperature linearly decrease with the increase of the Si content.The deviation of the structure is attributed to the atomic size effect.Based on Stearns theories,the decrease of the itinerant 3d... |
| Keywords: | magnetic properties Heusler alloys structural phase transition |
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