[en] We present upper critical field measurements on the superconducting oxides RE Ba₂Cu₃O_7-δ (RE = Y, Gd) performed in a pulsed magnetic field up to 43 T. Values as high as 52 T and 77 T for Y and Gd respectively, are expected at 77 K. However, in order to observe no resistive behaviour up to 43 T the temperature must be decreased down to 50 K. In the case of oxygen deficient systems the magnetoresistance reveals two superconducting phases which could be related to two different orders of oxygen vacancies

[en] Magnetoresistance measurements in NbSe₃ at 1.9 K and up to 52 T have been performed in pulsed magnetic fields. The data have been extensively interpreted in terms of Shubnikov-de Haas oscillations and are consistent with this interpretation. The application of the magnetic-breakdown model of Sowa and Falicov at NbSe₃ is at first sight questionable. (orig.)

[en] The YBa₂Cu₃O₇ compound has been prepared as a single-phase material. It exhibits a sharp superconducting transition around 93 K which is observed consistently by resistance and magnetic-susceptibility experiments. Upper critical fields H_c2 have been measured just below T_c up to 42T, using a high pulsed magnetic field. We conclude that the H_c2 value at 77K is about 80T and that the extrapolated value at O.OK could exceed 250T

[en] Measurements of the magnetoresistance of La₂CuO_4+y single crystals in magnetic fields up to 35 T are reported. The behaviour of ρ(T, H) remarkably depends on the heat treatment of the crystals in various chemical O₂ potentials. The thoroughly oxidized crystal shows a superconducting transition at 38 K, with a small value ΔT = 2 K. The upper critical field H_c2 for HparallelCuO-planes is 35 T (T = 10 K, 0.5ρ_n value). For the thoroughly reduced La₂CuO₄ crystal the resistivity increases strongly with decreasing temperature. For magnetic fields applied parallel to the CuO-planes, a magnetic transition is observed between 5 T and 6 T for La₂CuO_4+y crystals with different oxygen content. The temperature dependence of the spin-flop transition is observed in insulating La₂CuO_4+y. (orig.)

[en] The transverse magnetoresistance of (TMTSF)₂PF₆ has been investigated in magnetic fields up to 32 T, at low temperatures down to 4.2 K. Shubnikov-de-Haas oscillations are directly observed on the magnetoresistance in fields higher than 18 T, but there is no evidence of a threshold field since the disappearance of oscillations can be explained by the normal field-dependent damping. However these oscillations vanish very quickly between 5 and 4,2 K. This unusual behaviour could be related to a phase-transition. Finally an exploration of the fundamental field versus theta is given (theta = angle between B and c*), showing the warping of the ''Fermi tubes'' along the c* axis

[en] The technique of cantilever magnetometry has been extended to pulsed magnetic fields. Using micromachined single-crystal silicon cantilevers and capacitance detection, a utilizable sensitivity of ∼ 10^-12 Am² in fields up to 36 T has been achieved. Mechanical resonance studies and torque magnetization measurements on a microcrystal of YBa₂Cu₃O₇ demonstrate the feasibility of the technique in 'long pulse' magnets. Prospects for short pulse magnets are discussed

[en] Transverse magnetoresistance of the organic conductor (TMTSF)₂NO₃ has been measured at ambient pressure, up to 37 T, in the range 2-77 K. Both semiclassical magnetoresistance and quantum oscillation features are studied in connection with anion ordering and SDW transitions. (orig.)

[en] Transverse magnetoresistance measurements were performed in pulsed magnetic fields up to 37 T in the metallic state and the semimetallic charge-density wave ground state of (TSeT)₂Cl. Cooling with two different rates from 30 K down to 4.2 K yields two Shubnikov-de Haas oscillation frequencies. The 0⁺ Landau level is evidenced for both oscillation series. (orig.)

[en] The very sharp metal-insulator transition, which occurs at 8K at ambient pressure in λ-(BETS)₂FeCl₄ is suppressed when applying magnetic fields >10 T. This unusual phenomenon may be connected to ferromagnetic ordering of the Fe³⁺ moments, which could drive some ''evaporation'' of the previously condensed conduction electrons, into a field-restored highly conducting state (FRHCS) in which oscillations of the magnetoresistance are reported. (orig.)