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We demonstrate electrical detection of spin currents in metallic nanostructures. In a conductor with nonzero spin-orbit coupling, a spin current is predicted in a direction perpendicular to the applied electric field, giving rise to a spin Hall effect, where electrons with opposite spin orientations accumulate at opposite edges of the sample. Conversely, when a spin current is present, a charge imbalance is expected, following the Onsager reciprocal relations between spin and charge currents. We report direct electronic measurements of this effect in a lateral geometry by using a ferromagnetic electrode in combination with a tunnel barrier to inject a spin-polarized current in a paramagnetic conductor. We observe a laterally induced voltage in the latter that results from the conversion of the injected spin current into charge imbalance owing to the spin-orbit coupling. Such a voltage is proportional to the component of the injected spins that is perpendicular to the plane defined by the spin-current dire...

High‐speed transportation vehicles (trains) carrying superconducting magnets can be levitated by repulsion from diamagnetic currents induced in a conducting track. Various approximate methods are presented for calculating the lift and drag forces for such magnetic suspensions. Fourier analysis of periodic train magnet fields is used to analyze ``image‐force'' and ``hybrid null‐flux'' systems which involve homogeneous conducting sheet tracks. A lumped circuit analysis is used to discuss the ``null‐flux'' principle and related systems with structured tracks. The stability and efficiency of linear induction and linear synchronous motor propulsion systems are studied using related methods.

The far infrared spectral region (~ 10–100 cm−1) corresponds to kT for T = 15–150°K or βH for H = 105–106 oe. Materials with characteristic temperatures or fields of these orders of magnitude may have interesting far infrared spectra. We have studied far infrared resonance spectra in antiferromagnetic and in ferromagnetic rare-earth iron garnets.

A rather general relation is derived between vertical accelerations of the train and cryogenic power dissipation due to ac currents induced in the superconducting suspension magnets. Our theoretical results account for the order of magnitude of the rather large losses observed in the Fuji Electric test vehicle, which used less than state‐of‐the‐art conductors. Even with parameters estimated to represent the best commercially available materials, however, it appears that these losses may be comparable with the total heat leak due to all other causes if the accelerations are as large as permitted by subjective human ride quality considerations. Empirical data on losses under appropriate conditions of B, Ḃ, and I/Ic may be needed to ascertain whether improved materials will be required to avoid serious design constraints by cryogenic heating.

Measurements of the magnetic resonance absorption in CoCl2·2H2O over the frequency range from 18 to 50 cm−1 are briefly reported. Resonance lines are observed in fields up to 55 kOe, covering all three of its magnetic phases. The rather complex spectrum suggests that we observe not only simple, single excitations but also clustered, multiple ones, in which m > 1 spins are flipped. The energy required to create such an m‐fold excitation is much less than m times the energy to create a single excitation. This and other major features of the experimental data are accounted for by application of the cluster model of Date and Motokawa, which describes spin clusters in the ferromagnetic chains of CoCl2·2H2O.