High-resolution magnetization studies of the heavy-fermion superconductor CeCu2Si2 at very low temperatures and in high magnetic fields

Abstract

We report high-resolution dc-magnetization measurements on high-quality stoichiometric single crystals of CeCu2Si2 at very low temperatures down to 50 mK and in high magnetic fields up to 115 kOe, especially focusing on the as yet still unidentified phase A (and B at higher fields) that competes for stability with the heavy-fermion superconductivity. Anomalies at the A/B phase transitions are clearly observed in both the temperature and the field dependence of the magnetization. In isothermal magnetization curves M(T=const,H) at 50 mK, a metamagneticlike first-order transition is observed at 71 kOe and 30 kOe for H‖a and c, respectively. The magnitude of the magnetization jump at the first-order transition is only 2×10−3μB/Ce and 8×10−4μB/Ce for H‖a and c, respectively. Detailed magnetic phase diagrams are presented for both field orientations. The present results are consistent with a scenario that both A and B phases are spin-density-wave-type long-range-ordered states, where the ordered moments are of the order of 10−3μB/Ce.

Source-reported materials — not catalogue approval

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