We report measurements of magnetothermopower and magnetoresistivity as a function of temperature on RuSr 2 Gd 1-x La x Cu 2 O 8 (x = 0, 0.1). The normal-state thermopower shows a dramatic decrease after applying a magnetic field of 5 T, whereas the resistivity shows only a small change after applying the same field. Our results suggest that RuO 2 layers are conducting and the magnetic field induced decrease of the overall thermopower is caused by the decrease of partial thermopower associated with the spin entropy decrease of the carriers in the RuO 2 layers.

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We have measured the low-temperature specific heat C(T) for polycrystalline MgB 2 prepared by high pressure synthesis. C(T) below 10 K vanishes exponentially, which unambiguously indicates a fully opened superconducting energy gap. However, this gap is found to be too small to account for T c of MgB 2 . Together with the small specific heat jump ∆C/γ n T c =1.

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