Magnetic properties of Gd3+ ions in the spatially distributed DNA molecules

Magnetic properties of DNA liquid-crystal dispersions are experimentally investigated by SQUID magnetometer. The magnetic susceptibility of pure DNA and DNA doped by La, and Gd is measured in the region 4.2-300 K. The total magnetic moment is represented as a sum of the paramagnetic part and negative diamagnetic part. The number of paramagnetic Gd3+ ions is calculated in a good agreement with the number of phosphate complexes. The temperature dependence of magnetic susceptibility indicates the presence of interaction between Gd3+ magnetic moments, which is discussed in terms of long-range RKKY-type exchange in one-dimensional metals.