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Studies on controle method of structural and physical properties of quasicrystals

准晶结构和物理性质控制方法的研究

基本信息

批准号：
11640345
负责人：
ISHIMASA Tsutomu
金额：
$ 2.3万
依托单位：
HOKKAIDO UNIVERSITY (2000)Nagoya University (1999)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640345/
关键词：
quasicrystals icosahedral phase superlattice ordered state Al-Pd-Mn Zn-Mg-Ho F-type electrical resistivity ZN-Mg-Ho F2型 F2M型

项目摘要

In order to clarify physical properties of a quasicrystal, we have carried out careful investigation of quasicrystal structure and the relation between the structural perfection of quasicrystals and the physical properties such as magnetic susceptibility, electrical resistivity and magneto resistance. The Al-Pd-Mn and Zn-Mg-Ho quasicrystals were selected for this purpose, both of which belong to so-called "ideal quasicrystal" group. With respect to the Al-Pd-Mn, it was found that the F-type icosahedral quasicrystal, which is stable at high temperature, becomes unstable below approximately 750 C, and transforms to a complicated modulated quasicrystal at the alloy composition of Al71Pd21 Mn8.On the Zn-Mg-Ho icosahedral quasicrystals, it was discovered that the degree of F-type chemical ordering depends on the alloy composition ; highly ordered state realized only near the composition of Zn60Mg30Ho10. Further, increase of annealing temperature causes decrease in the intensity of superlattice reflections in the X-ray diffraction pattern. It was experimentally shown that the decreuse of the intensity is related to change of behavior of electrical resistivity and magneto resistance. This result opened the new controlling method of physical properties of quasicrystals by changing chemical ordering and thus degree of perfection of quasiperiodicity.

为了弄清准晶的物理性质，我们对准晶的结构以及准晶的结构完整性与其磁化率、电阻率和磁阻等物理性质之间的关系进行了细致的研究。Al-Pd-Mn准晶和Zn-Mg-Ho准晶都属于理想准晶族。对于Al-Pd-Mn准晶，发现在高温下稳定的F型二十面体准晶在750 ℃以下变得不稳定，并在合金成分为Al_（71）Pd_（21）Mn_（8）时转变为复杂的调制准晶。对于Zn-Mg-Ho准晶，发现F型化学有序程度与合金成分有关;高有序态仅在Zn_（60）Mg_（30）Ho_（10）组分附近实现。此外，退火温度的增加导致X射线衍射图案中的超晶格反射的强度降低。实验表明，磁场强度的衰减与电阻率和磁阻特性的变化有关。这一结果开辟了通过改变化学有序性进而控制准周期性完善程度来控制准晶物理性质的新方法。