Numerous measurements of saturation magnetization of Fe and Ni are reported. Saturation magnetization is determined by consideration of all contributions in the change of magnetization in high magnetic fields, i.e., internal demagnetizing fields, homogeneous rotations, and paramagnetic terms. The value found for the absolute saturation of iron is σ0,∞ = 221.71±0.08 emu/g, corresponding to M = 2.216 μB, in good agreement with previously accepted values. For Ni, the absolute saturation value obtained is σ0,∞ = 58.57±0.03 emu/g, corresponding to M = 0.616 μB, in good agreement with other previous data but 1.6% larger than the Weiss and Forrer's value of M = 0.606 μB.

In internal medicine, a simple method for the functional examination of the gastrointestinal tract without the risk of radiation exposure is required. We describe a novel principle based on the monitoring of magnetic markers which meets these demands. Our method employs a special permanent magnet which is repeatedly aligned by a vertically oriented pulsed magnetic field. Due to this alignment, the marker position can be derived from the stray field components measured by commercial field sensors. Our method was evaluated by means of a 3D intestinal phantom. The monitoring procedure yielded the time course of the marker position as a 3D plot either in real-time or as a time-lapse movie. The spatial resolution, expressed by the mean square deviation, was better than 10 mm and is thus sufficiently high to distinguish between adjacent loops of the gut. The temporal resolution, i.e. the minimum time between two successive measurements, was about 1 s. The presented method has very moderate technical demands and allows us to monitor magnetic markers in real-time. The technique may be useful with respect to functional examination of the gastrointestinal tract. In pharmaceutical research, our method offers the opportunity for remote drug release at any position of the gut.

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Superconducting properties of small crystals can be investigated by means of torque measurements. As an example the results obtained with a YBa2Cu3O7−x crystal of 1.5 × 10−5 cm3 at 79 K in external fields ranging from 2 to 150 kA/m are presented. The torque can be described in terms of a phenomenological model and yields information on different properties. Hc1 values are found of approximately 12 kA/m parallel to the c‐axis and 2 kA/m in the a–b‐plane, respectively. Anisotropic relaxation behaviour and a considerable anisotropy of rotational losses are observed which may be explained in terms of creation, annihilation, and motion of flux lines.