On the Paramagnetic Rotation of Tysonite
On the Paramagnetic Rotation of Tysonite
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DOI：
10.1103/physrev.46.17
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发表时间：
1934-07
期刊：
影响因子：
--
通讯作者：
J. V. Vleck;M. H. Hebb
中科院分区：
文献类型：
--
作者：
J. V. Vleck;M. H. Hebb
从理论上和对Leiden对Ce {\math {F}}_{3}$和tysonite的实验数据的检验都表明，稀土化合物中的Verdet常数V$应表现出与磁化率V$相同的对温度的依赖关系，即使在不遵守居里定律的情况下也是如此。由于$V$和$\ensuremath{\chi}$的温度变化模式相似，现有的关于$\ensuremath{\chi}$的温度变化的数据可以通过利用贝克勒尔和德哈斯的法拉第测量来大大增强。特别地，关于单个结晶轴的$\ensuremath{\chi} \ mathm {s}$的资料因此可以在钛土中得到，用结晶电位计算磁化率的试验也相应地变得严格起来。Kramers提出的三斜场似乎不能解释单个主磁化率的行为，尽管足以说明晶体粉末的平均特性。初步假设局部场具有菱形对称，菱形轴的三种可能的取向彼此相差120\ifmmode^\circ\else\textdegree\fi{}，从而使晶体具有所需的六边形对称性，与实验结果有较好的一致性。这种交错的菱形场与Oftedal对泰森土晶体结构的x射线分析是一致的，只是场与轴向特征的偏差似乎相当大。
It is shown both theoretically and by examination of the Leiden experimental data on Ce${\mathrm{F}}_{3}$ and tysonite that in rare earth compounds the Verdet constant $V$ should exhibit the same dependence upon temperature as does the magnetic susceptibility $\ensuremath{\chi}$, even when Curie's law is not obeyed. In consequence of the similarity in the mode of variation with temperature for $V$ and $\ensuremath{\chi}$, existing data on the temperature variation of $\ensuremath{\chi}$ can be considerably enhanced by drawing upon the Faraday measurements of Becquerel and de Haas. In particular, information concerning the $\ensuremath{\chi}'\mathrm{s}$ for individual crystallographic axes thus becomes available in tysonite and the tests of calculations of the susceptibility with crystalline potentials become correspondingly severe. The triclinic field proposed by Kramers for tysonite does not appear to account for the behavior of individual principal susceptibilities, although adequate for the mean characteristic of a crystal powder. It is shown that somewhat better agreement with experiment can be achieved by assuming tentatively that the local field has rhombic symmetry, with three possible orientations for the rhombic axes differing from each other by 120\ifmmode^\circ\else\textdegree\fi{}, so that all told the crystal has the desired hexagonal symmetry. Such staggered rhombic fields are compatible with Oftedal's x-ray analysis of the crystallographic structure of tysonite, except that the deviations of the fields from axial character seem rather large.