论文标题
夹紧对温度引起的价值过渡的夹具效果$ _2 $ _2 $ si $ _2 $薄膜在MGO上生长（001）
Clamping effect on temperature-induced valence transition in epitaxial EuPd$_2$Si$_2$ thin films grown on MgO(001)
论文作者
论文摘要
散装EUPD $ _2 $ SI $ _2 $显示了Europium温度驱动的价值转换，从$ \ sim $+2高于200 K到$ \ sim $+3以下100 k以下，这与大约2％的水晶晶体沿两个A轴沿两个A-axes的晶体晶体缩小相关。由于晶格和电子自由度之间的这种互连，外在薄膜中应变的影响特别有趣。环境X射线衍射（XRD）证实了Tetragonal Eupd $ _2 $ _2 $ si $ _2 $在MGO（001）上的外延关系，并在薄膜上具有离平面的C轴向取向，从而使两个晶格的A轴对齐。低温下的XRD揭示了薄膜晶格与底物的强耦合，在300至10 K的温度范围内没有突然的压缩。硬X射线光电子光谱在300和20 K时揭示了EU的温度独立于+2.0的温度独立价值。建议冷却时不断发展的双轴拉伸应变以抑制价值转变。取而代之的是，磁场中电阻率和霍尔效应的低温传输测量值高达5 t点，即在16-20 K处的膜厚度独立相变，表明磁有序。
Bulk EuPd$_2$Si$_2$ show a temperature-driven valence transisition of europium from $\sim$+2 above 200 K to $\sim$+3 below 100 K, which is correlated with a shrinking by approximatly 2 % of the crystal lattice along the two a-axes. Due to this interconnection between lattice and electronic degrees of freedom the influence of strain in epitaxial thin films is particularly interesting. Ambient X-ray diffraction (XRD) confirms an epitaxial relationship of tetragonal EuPd$_2$Si$_2$ on MgO(001) with an out-of plane c-axis orientation for the thin film, whereby the a-axes of both lattices align. XRD at low temperatures reveals a strong coupling of the thin film lattice to the substrate, showing no abrupt compression over the temperature range from 300 to 10 K. Hard X-ray photoelectron spectroscopy at 300 and 20 K reveals a temperature-independent valence of +2.0 for Eu. The evolving biaxial tensile strain upon cooling is suggested to suppress the valence transition. Instead low temperature transport measurements of the resistivity and the Hall effect in a magnetic field up to 5 T point to a film thickness independent phase transition at 16-20 K, indicating magnetic ordering.
