摘要
用真空电弧熔炼制备(Gd1-xDyx)5Si4(x=0.1,0.2,0.3,0.35)和(Gd1-xHox)5Si4(x=0.05,0.15,0.25)系列合金,在950℃下168h的真空热处理后,对其晶体结构、居里温度进行了研究。室温XRD分析发现该系列合金仍保持Gd5Si4的Sm5Ge4正交型结构,采用Rietveld法分析计算发现合金晶格常数随着x量的增加而逐渐减小。试样M-T磁化曲线测量结果表明:居里温度Tc在336K^260K连续可调,改变RE的含量可以得到不同的居里温度Tc;Tc近似呈线性变化,由此得出估计(Gd1-xREx)5Si4(RE=Dy,Ho)的Tc的计算公式。
Although the Gd5Si4 alloys exhibit the second-order phase transition and the large magnetic entropy change in the near room temperature, its Curie temperature is single. To search the new magnetic refrigeration materials which Curie temperatures are tunable in the range of near room temperatures, the authors of this paper researched on the crystal structure and the Curie temperatures of （Gd1-xDyx）5Si4（x=0.1, 0.2, 0.3, 0.35） and （Gd1-xHox）5Si4（x=0.05, 0.15, 0.25） alloys that were prepared by arc melting in an argon atmosphere. The vacuum heat treatment of the alloys was carried out at 950℃ for 168 h. X-ray diffraction patterns reveal that orthorhombic Gd5Si4-type structure remains unchanged. The lattice parameters, cell volumes, and x-ray densities were estimated using the Rietveld method. It shows that the lattice parameters decrease gradually in the （Gd1-xREx）5Si4（RE=Dy, Ho） alloy system with increasing Dy or Ho concentration. The results of magnetization versus temperature experiment show the Curie temperatures of （Gd1-xREx）5Si4 systems are tunable continually from 336 K to 260 K and the desired Curie temperature can be obtained with the different RE content. It was found that the Tc3 of the alloys decrease almost linearly with increasing x. As a result, a formula used to estimate the Curie temperature was obtained.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2006年第2期316-319,共4页
Rare Metal Materials and Engineering
基金
国家"863"基金资助项目(2002AA324010)
关键词
磁制冷材料
晶体结构
居里温度
磁化强度
晶格常数
magnetic refrigeration materials
crystal structure
Curie temperature
magnetization
lattice parameters
