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We report the experimental observation of resonant coupling and amplification of acoustic surface waves on a piezoelectric with electron surface waves on an adjacent semiconductor in a transverse magnetic field. Room‐temperature measurements were made at 30 and 150 MHz on a LiNbO3–GaAs structure, using magnetic fields of up to 144 kG.

A transient increase of the temperature of the surface of a type II superconductor cooled in a static magnetic field causes flux expulsion and enhances the final diamagnetic moment. It is argued that a net paramagnetic current is induced at the surface of the specimen during the initial cooling in a static magnetic field. Quenching of this surface current by a heat pulse permits flux expulsion.

The level of conduction and induced currents required for the onset of entry or exit of flux in an ``infinite'' slab of Nb (25%) Zr ribbon cooled through Tc in a static, parallel magnetic field depends on the sense of the currents. A small Meissner effect is observed in this material. We argue that a net paramagnetic current is induced in the surface layer during cooling through Tc in a static field H < Hc2.

The first EPR measurements of the identity of defects in an ion‐implanted layer (< 15 000 A) are reported. The Si–P3 center is the dominant paramagnetic defect produced at room temperature by 400‐keV O+ implantation in Al‐ and B‐doped Lopex Si, and it anneals below 200°C. The Si–P1 center is the dominant defect remaining above 200°C, and it anneals near 350°C. Interstitial Al++ (Si–G18) are observed in the Al‐doped sample; their number indicate that Si interstitials do not migrate over large distances into the unirradiated Si. Comparison of EPR and infrared data indicates that the Si divacancy is produced in the diamagnetic neutral charge state.

It is the purpose of this Letter to present some experimental evidence of the down shift of the conduction band edge when CdCr2Se4 crystals change from the paramagnetic to the ferromagnetic state. The anomalous electrical conductivity versus temperature behavior of indium‐doped, n‐type CdCr2Se4 is attributed to the movement of the conduction band edge and the resultant free carrier concentration increase in the conduction band. Photovoltaic measurements are made on p‐n junctions fabricated on single crystals grown by liquid‐transport techniques. The temperature dependence of the optical band gap determined by photovoltaic measurements is in good agreement with absorption measurements reported by Harbeke and Pinch.

The change of the saturation magnetization of Fe films with the pressure of nitrogen during deposition ranging from 2 × 10−5 to 7 × 10−3 Torr has been investigated systematically. We found a new magnetic material which has the highest saturation magnetization at room temperature, 2050 G, among those of all the magnetic materials. This was attributed to Fe16N2, which has a bct structure, and the magnetic moment associated with Fe atoms of Fe16N2 was deduced to be 3.0 μB.

Thermoluminescence of rare‐earth doped BaF2, irradiated with x rays at 77°K, is interpreted in terms of the appearance and disappearance of three paramagnetic hole centers. One of the centers is associated with an interstitial fluorine.

We have aligned the liquid crystal molecules of 4, 4′‐di‐n‐heptyloxyazoxybenzene in the smectic C mesophase by means of a magnetic field. With the aid of a paramagnetic probe, we have studied the effect of rotation of the aligned sample in the magnetic field of the EPR spectrometer. Interpretation of the results enables us to determine the tilt angle of the liquid crystal, and to predict that smectic C liquid crystals would not lend themselves to NMR orientation studies because of molecular reorientations.

The maximum rate at which paramagnetic ions in a crystal lattice can respond to a modulating magnetic field superimposed on a static magnetic field is determined by the characteristic relaxation time of the ions. At low temperatures and nonzero static magnetic field the spin‐lattice relaxation time (τ) is the dominant characteristic relaxation time. The influence of τ at low temperatures on the phase and amplitude of the ac Faraday rotation is quantitatively described. Experimental results for Eu2+‐doped CaF2 are reported which verify the theoretical concepts and yield τ values at 9°K which vary linearly with the applied static magnetic field.

Parametric magnetic Δm = ±2 nuclear spin transitions are observed when an rf magnetic field at the frequency (Em−2 − Em)/h is applied parallel to a large, externally applied, magnetic field in a ruby crystal where the symmetry axis of the cylindrically symmetric electric field gradient tensor (the c axis in ruby) is perpendicular to the external magnetic field.

Some divalent europium compounds (EuS, EuSe, EuTe) are made by formerly used procedures, and their magnetic properties are examined and compared with EuO characteristics. At 4.2 K, the sulfide and selenide are ferromagnetic and the telluride is paramagnetic. Graphs display various temperature and magnetic variations. (D.C.W.)

Electric or magnetic fields acting on the anisotropy of the electric or magnetic susceptibility exert torques within a liquid crystal which may compete with the elastic torques determining its internal structure. A general method is presented for calculating the structural changes thus produced. Two examples are given, and the field strength for the effects is estimated to be 105 V/cm or 105 G. Two experiments are suggested to test the theory.

The ground-state properties of Yb/sup 3+/-doped yttrium oxide were investigated by means of paramagnetic resonance techniques. For a general orientation of the d-c magnetic field, 10 resonance lines were observed. For the magnetic fleld confined to the (110) plane, 7 lines were observed. The absorption spectrum at 4.2 un. Concent 85% K as a function of magnetic field orientation in the (l10) plane for a 0.5% Yb concentration is presented. (C.E.S.)

Electrical conductivity for ultrasound propagating parallel to the dc magnetic field is calculated by using a quantum treatment which is valid at high frequencies. The energy band structure is assumed to be the Cohen nonellipsoidal nonparabolic (NENP) model. The results show that the ac longitudinal conductivity depends on the magnetic field, and some oscillations and discontinuities occur in the dependence of the conductivity on the magnetic field in the region of high frequencies and strong magnetic fields.

The paramagnetic resonance spectra of Mn/sup 2+/, Fe/sup 3+/, and Nd/sup 3+/ ions in CaWO/sub 4/ were investigated, and it was found that Nd/sup 3+/ can occupy both the Ca and W sites whereas Mn/sup 2+/ is found only in the Ca site and Fe/sup 3+/ only in the W site. It is concluded that the CaWO/sub 4/ lattice can be host to trivalent paramagnetic impurities in either the Ca or W site. (C.E.S.)

We propose a magnetic mirror probe method for measurement of the electron temperatures of a magnetized plasma parallel and perpendicular to a magnetic field. The most simple magnetic mirror probe is introduced which is made of ferromagnetic spherical metal.