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A study of the structural and electronic phase diagram of Pr-doped ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$ is presented in order to investigate whether there is an influence of the high-temperature tetragonal-to-orthorhombic phase transition on the disappearance of superconductivity in the overdoped region. We find that Pr doping shifts the structural phase boundary to higher Sr concentrations, but that superconductivity occurs in the same Sr-concentration range as in ``pure'' ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$. Thus, the disappearance of superconductivity is not related to the high-temperature structural transition, but is determined predominantly by the hole concentration in the CuO planes.

We have studied the low-field Meissner effect of polycrystalline Bi high-temperature superconductors using a special superconducting-quantum-interference-device magnetometer. In certain samples a surprising feature was observed: Instead of the usual diamagnetic moment a paramagnetic moment develops in the field cooling mode below ${\mathit{T}}_{\mathit{c}}$ for fields H1 Oe. The data are consistent with orbital paramagnetic moments due to spontaneous currents. Such currents may originate in so-called \ensuremath{\pi} contacts in the weak-link network of polycrystalline material. In some of these samples also an anomaly in the low-field microwave absorption was observed, which is obviously correlated with the existence of spontaneous currents.

We report the measurement of the dynamic magnetic susceptibility of an intermediate-valence Eu compound in inelastic neutron scattering experiments, namely, on a sample of EuPd 2 Si 2 with enriched 153 Eu. The most remarkable feature is an increase of the quasielastic linewidth with decreasing temperature, which is apparently a consequence of the well-known temperature-driven valence change. Moreover, at low temperatures a strong inelastic line is observed, which is interpreted as a multiplet transition within the Eu 3+ configuration (J=0→J=1). To check the quality of the sample, additional Mossbauer and magnetization measurements were performed. From these we conclude a fraction of approximately 6% of the so-called "satellite" phase in our sample, which is ferromagnetic at low temperatures and whose effects can be separated consistently out of all of our data.