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Powder neutron diffraction measurements were carried out to investigate the magnetic structure of the antiferromagnet NdRh2Zn20. The magnetic reflections observed for T ≤ 1.0 K are indexed by the propagation vector of k = (1/2, 1/2, 1/2). From the analysis of the intensity of magnetic reflections, a magnetic structure described by the Γ6 representation is proposed. The magnetic moments are parallel to the [ 11 2 ¯ ] or [ 1 ¯ 10 ] direction and stacked with a sequence of up-up-down-down along the [111] direction.

We have measured the electrical resistivity as a function of temperature up to pressures of 25 GPa of pure fullerenes C60, C70 and the compound C60I4. For the three materials the best fit in our temperature range corresponds to a three-dimensional variable-range hopping conductivity, signature of an important disorder. A dramatic decrease of the resistivity, by two orders of magnitude per GPa, is observed at low pressures. However, no metallic state is attained as all the samples present a phase transformation in the high-pressure range, probably originated by the crossover from sp2 to sp3 hybridization of the carbon orbitals at high pressures.

We have measured the electrical resistivity of NbSe3 between 2 K and room temperature up to a pressure of 7.2 GPa. At P1 = 3.5 GPa we observe the extinction of the high-temperature charge density wave (T1-CDW) and the enhancement of the superconducting critical temperature Tc to 5 K. The logarithmic pressure slopes of T1 (P P1) are found to be practically equal. A similar behaviour had been reported previously at lower pressures for T2 (P < P2) and Tc (P2 < P < P1) in the distorted state. We discuss these results in terms of an anisotropic superconducting state in NbSe3, with different gaps associated with different types of chains.

The magnetic phase diagrams of hexagonal R2PdSi3 compounds have been found to feature an apparent similar phase when the field is applied along the respective magnetic easy axes. To elucidate this, neutron diffraction on single crystalline Tb2PdSi3 and Ho2PdSi3 in magnetic fields was performed. These two compounds have different magnetic structures in zero field. In Tb2PdSi3 the propagation vector is parallel to the hexagonal axis while in Ho2PdSi3 the propagation is in the basal plane. In both compounds the magnetic moment direction is perpendicular to the propagation vector. The application of a magnetic field along the respective easy axes destroys the zero field magnetic structure and leads to a ferrimagnetic phase with magnetic intensity on the same positions for both compounds. These findings and their connections to the crystallographic (super-)structure are presented and discussed.

The origin of the metamagnetic-like transition occurring in the heavy-fermion compound CeRu2Si2 has been investigated by means of high-pressure magnetization and resistivity measurements. The zero-field results reveal an extremely strong pressure sensitivity of the Fermi-liquid state, with a huge electronic Grüneisen parameter of about +170. Almost the same value is found for the characteristic field H M of the transition. The magnetostriction is correspondingly large and can be quantitatively accounted for if one assumes the magnetization to obey a simple scaling relation as a function of pressure.