De Haas-van Alphen effect in uranium and ytterbium Compounds

在稀土离子之间的最近邻距离d&lt；R-R&gt；小于某一临界值，几乎等于0.45 nm的Yb和铀化合物中，观察到了价态涨落和重费米子现象。D&lt；R-R&gt；的降低预计将增加稀土离子的传导电子和4-f电子之间的杂化。在本工作中，我们测量了YbZn；11&gt；(d_&lt；R-R&gt；=0.569 nm)，YbSn3(d_&lt；R-R&gt；=0.468 nm)，YbBi2(d_&lt；R-R&gt；=0.420 nm)，YbAl3(d_&lt；R-R&gt；=0.420 nm)和UGA_2(d_&lt；R-R&gt；=0.420 nm)的Dhaas-van Alphen效应。=0.400 nm)。为了研究导电电子和4-f电子的杂化对费米表面性质的影响。对YbSn3的结果表明，dHvA频率在60T到3000T之间，回旋质量在0.13m0到0.44m0之间，其中m0是自由电子质量。对于YbZn_11&gT，dHvA的频率范围为200~11000T，回旋质量与YbSn3的回旋质量基本相同。这些结果表明YbS…更多的N_3是补偿金属，YbSn3和YbZn_(11)中的Yb离子是二价的。UGA_2的dHvA频率从20T到1300T，观测到的回旋质量从0.3M_0到3.3M_0。它们比YbSn3和YbZn11&gt；大10倍。在UGA_2的最低频率振荡中观察到dHvA频率的场依赖关系。这些结果表明，UGA_2中的5f电子与传导电子发生了明显的杂化。我们还测量了作为YbAl3参考材料的LuAl3的de Haas-van Alphen效应。观测频率在400T到23kT之间，回旋有效质量在0.3m0到1m0之间。用全势线性化的APW方法计算了能带结构。通过计算解释了观测结果的总体特征。在高达15T的磁场中，在0.3K的温度下没有观察到YbAl_3的dHvA效应。我们将利用稀释式制冷机在较低温度下测量YbAl_3的dHvA效应。较少

Valence fluctuation and heavy Fermion phenomena are observed in ytterbium and uranium compounds that have the nearest neighbor distance d_<R-R> between rare-earth ions smaller than some critical value, nearly equal to 0.45nm. The decrease in d_<R-R> is expected to increase hybridization between conduction electrons and 4-f electrons of rare-earth ions. In the present work we have measured the de Haas-van Alphen effect of YbZn_<11> (d_<R-R>=0.569nm), YbSn_3 (d_<R-R>=0.468nm), YbBi_2 (d_<R-R>=0.420nm), YbAl3 (d_<R-R>=0.420nm) and UGa_2 (d_<R-R>=0.400nm) to investigate the dependence of the Fermi surface properties on the hybridization between conduction and 4-f electrons The results for YbSn_3 show that the dHvA frequencies range from 60T to 3000T and the cyclotron masses from 0.13m_0 to 0.44m_0, where m_0 is the free electron mass. For YbZn_<11> the dHvA frequencies range from 200T to 11000T and the cyclotron masses are nearly the same as those of YbSn_3. These results indicate that YbS … More n_3 is a compensated metal and Yb ions in YbSn_3 and YbZn_<11> are divalent. The dHvA frequencies of UGa_2 range from 20T to 1300T.The observed cyclotron masses range from 0.3m_0 to 3.3m_0. They are larger than those of YbSn_3 and YbZn_<11> by a factor of ten. Field dependence ofthe dHvA frequency is observed in the lowest frequency oscillations in UGa_2. These results indicate that the 5f electrons in UGa_2 hybridize appreciably with the conduction electrons. We have also measured the de Haas-van Alphen effect in LuAl3, which is a reference material for YbAl3. Observed frequencies range from 400 T to 23 kT.The observed cyclotron effective masses range from 0.3m0 to 1m0. A band structure calculation was carried out by a full potential linearized APW method. The gross feature of the observed results was explained by the calculation. The measurement of YbAl3 has not been observed at 0.3K in magnetic fields as high as 15T.We will try to measure the dHvA effect of YbAl_3 in lower temperatures using dilution refrigerator. Less