Spontaneous magnetostriction in R2Fe14B (R=Y, Nd, Gd, Tb, Er)
Spontaneous magnetostriction in R2Fe14B (R=Y, Nd, Gd, Tb, Er)
复制标题
DOI：
10.1016/j.jmmm.2004.12.040
复制
发表时间：
2005-08
影响因子：
2.7
通讯作者：
N. Yang;K. Dennis;R. McCallum;M. Kramer;Yuegang Zhang;P. Lee
中科院分区：
文献类型：
--
作者：
N. Yang;K. Dennis;R. McCallum;M. Kramer;Yuegang Zhang;P. Lee
用高能同步辐射X射线衍射法研究了化学计量比化合物R{sub2}Fe{sub14}B(R=Y，ND，Gd，Tb，Er)在10-1000K温度范围内的热膨胀反常，观察到了较大的因瓦效应和相应的较大温度依赖关系，晶格参数较居里温度(T{subc})以上约10-15K。在所有化合物中，a轴比c轴表现出更大的因瓦效应。计算了晶格和键的自发磁应变。结果表明，铁亚晶格对化合物的体积自发磁致伸缩起主导作用，稀土亚晶格的贡献与稀土的自旋磁矩大致成正比。键长变化与理论自旋密度计算结果一致。Fe中心周围的平均键磁应变与其磁矩近似成正比。
Thermal expansion anomalies of R{sub 2}Fe{sub 14}B (R=Y, Nd, Gd, Tb, Er) stoichiometric compounds were studied by X-ray diffraction with high-energy synchrotron radiation using a Debye-Scherrer geometry in temperature range of {approx}10-1000 K. A large invar effect with a corresponding large temperature dependence of lattice parameters {approx}10-15 K above their Curie temperatures (T {sub c}) are observed. The a-axes show a larger invar effect than the c-axes in all compounds. The spontaneous magnetostrain of the lattices and bonds are calculated. The iron sublattice is shown to dominate the volumetric spontaneous magnetostriction of the compounds and the contribution from the rare-earth sublattice is roughly proportional to the spin magnetic moment of the rare earths. The bond-length changes are consistent with the theoretical spin-density calculation. The average bonds magnetostrain around Fe sites is approximately proportional to their magnetic moments.