De Haas-van Alphen Effect of Heavy Electron Systems with non-Fermi Liquid behavior

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The Fermi surface study of CeNi2Ge2, which is a heavy electron system showing non-Fermi liquid behavior, by means of de Haas-van Alphen (dHvA) effect was intended. The method of crystal growth with very low residual resistivity was studied. Further, we perfoemed to measure the dHvA effect of the reference material LaNi2Ge2.RESULTS : A good quality single crystals could be obtained in the following conditions : 1) Pre-purification of the raw material of Ce using electro-transport method. 2) Growth along the [001] direction using the seed. For the best specimen, which was only obtained at the position up to 20 mm from the neck point of the single crystal rod, the residual resistivity was 1.5 μΩ cm and the half width of the X-ray rocking curve, (004) reflection, was 0.2 degrees. The dHvA effect of CeNi2Ge2 could not be observed, probably due to the heavy electron masses. We will try to observe at a temperatures lower than 3He temperature in a future. On the other hand, we suceeded to measure the dHvA effect of LaNi2Ge2, and compared to the Fermi surfaces calculated, obtaining very good agreement between the experiment and the band calculaion.We also studied the magnetic correlation and the superconductivity, using the inelastic nutron scattering and the electrical resistivity. It was found the weak antiferromagnetic correlation exists at temperatures lower than 30 K, and the superconductivity also was found at ambient pressure and at pressures from 2 GPa to 5 GPa at temperatures lower than 300 mK.