• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physical review >Pressure-induced structural, electronic, and magnetic phase transitions in FeCl_2 studied by x-ray diffraction and resistivity measurements
【24h】

Pressure-induced structural, electronic, and magnetic phase transitions in FeCl_2 studied by x-ray diffraction and resistivity measurements

机译：通过X射线衍射和电阻率测量研究了FeCl_2中压力诱导的结构，电子和磁性相变

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

High-pressure (HP) synchrotron x-ray diffraction (XRD) studies were carried out in FeCl_2 (T_N≈24 K) together with resistivity (R) studies at various temperatures and pressures to 65 GPa using diamond-anvil cells. This work follows a previous HP ~(57)Fe Mossbauer study in which two pressure-induced (PI) electronic transitions were found interpreted as: (ⅰ) quenching of the orbital-term contribution to the hyperfine field concurring with a tilting of the magnetic moment by 55°, and (ⅱ) collapse of the magnetism concurring with a sharp decrease in the isomer shift. The R(P,T) studies affirm that the cause of the collapse of the magnetism is a PI p-d correlation breakdown, leading to an insulator-metal transition at ～45 GPa and is not due to a spin crossover (S=2→S=0). The structure response to the pressure evolution of the two electronic phase transitions starting at low pressures (LP), through an intermediate phase (IP) 30-57 GPa, and culminating in a high-pressure phase, P>32 GPa, can clearly be quantified. The IP-HP phases coexist through the 32-57 GPa range in which the HP abundance increases monotonically at the expense of the IP phase. At the LP-IP interface no volume change is detected, yet the c axis increases and the a axis shrinks by 0.21 and 0.13 A, respectively. The fit of the equation of state of the combined LP-IP phases yields a bulk modulus K_0=35.3(1.8) GPa. The intralayer Cl-Cl distances increase but no change is observed in Fe-Cl bond length nor are there substantial changes in the interlayer spacing. The pressure-induced electronic IP-HP transition leads to a first-order structural phase transition characterized by a decrease in Fe-Cl bond length and an abrupt drop in V(P) by ～3.5% accompanying the correlation breakdown. In this transition no symmetry change is detected and the XRD data could be satisfactorily fitted with the CdI_2 structure. The bulk modulus of the HP phase is practically the same as that of the LP-IP phases suggesting negligible changes in the phonon density of state.
机译：使用金刚石砧盒在FeCl_2（T_N≈24K）中进行了高压（HP）同步加速器X射线衍射（XRD）研究，并在各种温度和压力至65 GPa的压力下进行了电阻率（R）研究。这项工作是在先前的HP〜（57）Fe Mossbauer研究之前进行的，在该研究中，发现两个压力感应（PI）电子跃迁解释为：（ⅰ）伴随磁场倾斜引起的轨道项对超精细场的贡献的猝灭力矩降低了55°，并且（ⅱ）的磁场崩溃伴随着异构体位移的急剧降低。 R（P，T）研究证实，磁场崩溃的原因是PI pd相关性击穿，导致绝缘体-金属在〜45 GPa时发生转变，而不是由于自旋交叉（S = 2→S = 0）。从低压（LP）开始，到中间相（IP）30-57 GPa，最后达到高压相（P> 32 GPa），对两个电子相变的压力演变的结构响应很明显量化。 IP-HP相共存于32-57 GPa范围内，其中HP丰度以IP相为代价单调增加。在LP-IP接口上，未检测到任何体积变化，但c轴增加而a轴收缩了0.21和0.13A。组合的LP-IP相的状态方程的拟合得出体积模量K_0 = 35.3（1.8）GPa。层内Cl-Cl的距离增加，但未观察到Fe-Cl键长的变化，层间间距也没有实质性变化。压力诱导的IP-HP电子跃迁导致一级结构相变，其特征是Fe-Cl键长减小，伴随相关性破坏，V（P）突然下降约3.5％。在此过渡过程中，未检测到对称性变化，并且XRD数据可以令人满意地与CdI_2结构相符。 HP相的体积模量实际上与LP-IP相的体积模量相同，表明状态声子密度的变化可忽略不计。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号