关于Gd5Si2Ge2的高温相变的研究
Yurij Mozharivskyj1, Alexandra O Pecharsky, Vitalij K Pecharsky
1Ames Laboratory, Materials and Engineering Physics Program, Iowa State University, Ames, Iowa 50011-3020, USA.
Journal of the American Chemical Society
|January 6, 2005
概括
在Gd(5) Si(2) Ge(2) 中的相变发生在300-320°C左右. 像氧气和气这样的杂质显著影响了这种过渡,这与之前的预测相反.
科学领域:
- 材料科学 材料科学 材料科学
- 固态物理 固态物理
- 晶体学 晶体学是指结晶学.
背景情况:
- 基于加多的化合物,如Gd(5) Si(2) Ge(2) 是关键的巨型磁热材料.
- 了解相位转换对于优化磁性制冷应用至关重要.
研究的目的:
- 为了研究在Gd(5) Si(2) Ge(2) 中从单临床到正合体 (β->gamma) 阶段的过渡.
- 检查间歇性杂质对这种过渡的影响.
主要方法:
- 在现场高温单晶X射线衍射.
- 开发一种专门的晶体安装技术,以防止污染.
主要成果:
- 在加热和缓慢冷却时,β->马过渡在300-320°C之间发生可逆性,但在快速冷却时不可逆性.
- 与预测相反,Si和Ge原子的分布在各阶段保持一致.
- 杂质,特别是氧气和气,显著改变过渡温度,在空气存在时仅在600°C完成过渡温度.
结论:
- 位于板间空隙中的间位杂质在Gd(5) Si(2) Ge(2) 的稳定性和过渡性行为中起着关键作用.
- 这项研究挑战了以前关于原子分布和杂质效应的理论模型.
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