Tb_2Fe_(15.5)Cr(1.5)化合物的本征磁致伸缩

Spontaneous magnetostriction of Tb_2Fe_(15.5)Cr(1.5) compound

通过x射线衍射及磁测量手段研究了Tb2 Fe1 5 5Cr1 5化合物的热膨胀性质及本征磁致伸缩性质 .研究结果表明Tb2 Fe1 5 5Cr1 5化合物在 2 93— 6 72K的温度范围内具有六角相的Th2 Ni1 7型结构 .在 4 32— 5 2 2K的温度范围内具有负热膨胀性质 ,其平均热膨胀系数 α =- 1 5 7× 10 - 5 K .对本征磁致伸缩的研究结果表明Tb2 Fe1 5 5Cr1 5化合物中存在着较强的各向异性的本征磁致伸缩 ,2 93K时其本征体磁致伸缩约为 8. 4× 10 - 3,晶格畸变主要发生在c轴方向上 .磁测量研究结果表明Tb2 Fe1 5 5Cr1 5化合物的居里温度约为 4 94K ,比其母合金Tb2 Fe1 7高约 80K .

The negative thermal expansion and spontaneous magnetostrictive deformation of Tb2Fe15.5Cr1.5 compound have been investigated by means of x-ray diffraction and magnetization measurements. The compound Tb2Fe15.5Cr1.5 has a hexagonal Th2Ni17-type structure from 293 to 672K. A negative thermal expansion was found from 432 to 522K. The coefficient of the average thermal expansion is (α) over bar = -1.57 x 10(-5)/K. There exists a strong and anisotropic spontaneous magnetostriction in the magnetic state of Tb2Fe15.5Cr1.5. The spontaneous volumetric magnetostrictive deformation is about 8.4 x 10(-3) at 293K and the deformation occurs mainly in the direction of c-axis. The result of magnetization measurement shows that the Curie temperature of Tb2Fe15.5Cr1.5 is 494K, which is by about 80K higher than the mother compound Tb2Fe17.