Giant anomalies of the thermal expansion at the spin-Peierls transition in CuGeO3.
Giant anomalies of the thermal expansion at the spin-Peierls transition in CuGeO3.
复制标题
CuGeO3 中自旋-佩尔斯转变处的热膨胀的巨大异常。
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
Dhalenne
中科院分区：
文献类型：
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作者：
Winkelmann;Gamper;Büchner;Braden;Revcolevschi;Dhalenne
用高分辨率电容膨胀仪测量了Spin-Peierls铜酸盐的热膨胀系数沿三个正交方向的热膨胀系数。我们在自旋-Peierls转变温度({\mathit{T}}_{\mathm{SP}}$)处观察到巨大的强各向异性反常，并观察到在${\mathit{T}}_{\mathrm{SP}}$以下所有三个晶轴上的自发应变。从数学和比热的跳跃中，我们估计了很大的单轴压力依赖关系，特别是对于垂直于一维{\mathrm{Cu}}^{2+}$链的压力。此外，我们还观察到相变上方热膨胀的反常温度依赖关系，与磁化率有惊人的相似之处。
The thermal-expansion coefficients \ensuremath{\alpha} of the spin-Peierls cuprate ${\mathrm{CuGeO}}_{3}$ have been measured along the three orthorhombic directions using a high-resolution capacitance dilatometer. We observe giant, strongly anisotropic anomalies at the spin-Peierls transition temperature (${\mathit{T}}_{\mathrm{SP}}$) and spontaneous strains along all three crystal axes below ${\mathit{T}}_{\mathrm{SP}}$. From the jumps of \ensuremath{\alpha} and the specific heat we estimate large uniaxial pressure dependencies of ${\mathit{T}}_{\mathrm{SP}}$, in particular for pressure applied perpendicular to the one-dimensional ${\mathrm{Cu}}^{2+}$ chains. In addition, we observe an anomalous temperature dependence of the thermal expansion above the transition showing a striking similarity to that of the magnetic susceptibility.