V.D. Kuznetsov

Magnetic Properties of Copper as a Constituent of Nanobridges Formed between Spatially Fixed Deoxyribonucleic Acid Molecules

The number of copper ions as constituents of a nanobridge that links two deoxyribonucleic acid (DNA) molecules that are fixed in a particle of a liquid-crystalline dispersion has been evaluated from the measurements of the magnetic susceptibility of particles in the liquid-crystalline dispersion of DNA. It has been shown that the experimental data are consistent with both theoretical assumptions on the possible structure of a nanobridge and a thermodynamic model that describes the formation of these bridges.

Extraordinary Magnetic Properties of Ca1–xEuxS and Sr1–xEuxS Solid Solutions

The electron paramagnetic resonance (EPR) spectra and the stationary magnetic susceptibility are investigated for Ca1–xEuxS and Sr1–xEuxS solid solutions (0.00005 < x < 0.0032). The EPR spectrum of Eu2+ in both matrices contains a wide structureless line in addition to the narrow lines of the superfine structure characteristic of ions with high local symmetry. Because of the extraordinary temperature dependence of this line in CaS:Eu, it is associated with strongly interacting magnetic centers, namely, exchange-coupling pairs and chains or more complex clusters of magnetic ions. At the same time, the dependence of the stationary magnetic susceptibility in the temperature range 4.2–50 K has no peculiarities for CaS:Eu and SrS:Eu and obeys the Curie law.