V Glazkov | PubMed Health

PubMed2005

Magnetic density of states at low energy in geometrically frustrated systems.

Using muon-spin-relaxation measurements we show that the pyrochlore compound Gd(2)Ti(2)O(7), in its magnetically ordered phase below approximately 1 K, displays persistent spin dynamics down to temperatures as low as 20 mK. The characteristics of the induced muon relaxation can be accounted for by a scattering process involving two magnetic excitations, with a density of states characterized by an upturn at low energy and a small gap depending linearly on the temperature. We propose that such a density of states is a generic feature of geometrically frustrated magnetic materials.

Journal Article↗

PubMed1989

Retinal damage from intense visible light.

Studies of laboratory animal retinal exposure to green monochromatic laser radiation show an increasing stability of tissue with increasing pulse duration up to 10(-1) s. This mechanism of biological response of the eye to light damage is fundamental to living systems. It does not manifest itself in animals under deep anesthesia. A mathematical model has been developed which permits one to predict the dependence of threshold injury of visible monochromatic radiation. The model is based on the assumption that the entropy of the reaction of thermal tissue denaturation decreases with increasing pulse duration. This may be used to refine safety standards for personnel working with lasers and to optimize the parameters of lasers used in ophthalmic surgery.

Animals↗