Magnetic Phase Diagram and Fermi Surface Properties of CeRu2(Si1-xGex)2

We report the magnetic, transport and de Haas–van Alphen (dHvA) effect measurements to investigate the evolutions of metamagnetic behavior and electronic structure with Ge concentration x in CeRu 2 (Si 1- x Ge x ) 2 . With decreasing x , the ground state changes from ferromagnetic state to antiferromagnetic state at x a = 0.58, then to paramagnetic state at x c = 0.065. When a magnetic field is applied parallel to the [001] direction, first order metamagnetic transition takes place in the anitferromagnetic state and it changes to metamagnetic crossover in the paramagnetic state at x c . It is also found that the metamagnetic behavior as well as the magnetic phase diagram qualitatively change at x b = 0.29. The transport and dHvA effect measurements have been performed with fields applied in the (001) plane for which no metamagnetic transition takes place. With decreasing x , the magnitudes of the residual resistivity at 0.5 K, the coefficient A of T 2 term in the temperature dependence of resistivity, the...