ABSTRACT
Ge(1-x)Mn(x)Te is shown to be a multiferroic semiconductor, exhibiting both ferromagnetic and ferroelectric properties. By ferromagnetic resonance we demonstrate that both types of order are coupled to each other. As a result, magnetic-field-induced ferroelectric polarization reversal is achieved. Switching of the spontaneous electric dipole moment is monitored by changes in the magnetocrystalline anisotropy. This also reveals that the ferroelectric polarization reversal is accompanied by a reorientation of the hard and easy magnetization axes. By tuning the GeMnTe composition, the interplay between ferromagnetism and ferroelectricity can be controlled.
ABSTRACT
Understanding the mechanisms controlling the spin coherence of electrons in semiconductors is essential for designing structures for quantum computing applications. Using a pulsed electron paramagnetic resonance spectrometer, we measure spin echoes and deduce a spin coherence time (T2) of up to 3 mus for an ensemble of free two-dimensional electrons confined in a Si/SiGe quantum well. The decoherence can be understood in terms of momentum scattering causing fluctuating effective Rashba fields. Further confining the electrons into a nondegenerate (other than spin) ground state of a quantum dot can be expected to eliminate this decoherence mechanism.
ABSTRACT
In a series of 30 unilaterally pseudophakic patients, electroretinograms and electrooculograms were recorded 6 months postoperatively. The unoperated on fellow eyes served as controls. High intraoperative retinal light exposure (3.4-7.3 mW/cm2, Zeiss OPMI6 operating microscope) caused a substantial reduction of electrophysiologic potentials. Light protection prevented deterioration of electroretinogram and electro-oculogram potentials; reducing the bulb voltage, tilting the axis of illumination, filtering short wavelengths and the use of light shields resulted in 4-log-unit lower intensities (0.8-3.7 microW/cm2).
Subject(s)
Intraoperative Complications/physiopathology , Light/adverse effects , Retinal Diseases/physiopathology , Aged , Aged, 80 and over , Cataract Extraction , Electrooculography , Electrophysiology , Electroretinography , Female , Humans , Lenses, Intraocular , Male , Microscopy , Middle Aged , Photoreceptor Cells/physiology , Retinal Diseases/diagnosis , Retinal Diseases/etiologyABSTRACT
Intentional overdosage of copper salts is seen infrequently in the U.S., but is fairly common in other countries (1). Toxic blood levels can be seen after oral ingestion of as little as one gram of copper sulfate in an adult (2). We report a case of a patient who ingested 250 grams of copper sulfate, developed transient hepatic dysfunction, and recovered after the prompt administration of chelation therapy.
