S. S. Sosin

Magnetocaloric effect in pyrochlore antiferromagnet Gd 2Ti 2O 7

An adiabatic demagnetization process is studied in

New magnetic states in copper metaborate CuB2O4

{\mathrm{Gd}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}

Spin dynamics of the pyrochlore magnets Gd2Ti2O7 and Gd2Sn2O7 in the paramagnetic state

, a geometrically frustrated antiferromagnet on a pyrochlore lattice. In contrast to conventional paramagnetic salts, this compound can exhibit a temperature decrease by a factor of 10 in the temperature range below the Curie-Weiss constant. The most efficient cooling is observed in the field interval between 120 and

Magnetic resonance in the pyrochlore antiferromagnet Gd2Ti2O7

60\phantom{\rule{0.3em}{0ex}}\mathrm{kOe}

Comparative study of ESR spectra in incommensurate antiferromagnets

corresponding to a crossover between saturated and spin-liquid phases. This phenomenon indicates that a considerable part of the magnetic entropy survives in the strongly correlated state. According to the theoretical model, this entropy is associated with a macroscopic number of local modes remaining gapless until the saturation field. Monte Carlo simulations on a classical spin model demonstrate good agreement with the experiment. The cooling power of the process is experimentally estimated with a view to possible technical applications. The results for

Investigation of the hyperfine interaction in the antiferromagnetic CsMnI3

{\mathrm{Gd}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}

Magnetic properties of defects in spin-gap magnets

are compared to those for

Magnetic resonance of the RbMnBr3 antiferromagnet under pressure

{\mathrm{Gd}}_{3}{\mathrm{Ga}}_{5}{\mathrm{O}}_{12}

The magnetic ordering in the mixed valence compound beta-Na0.33V2O5

, a well-known material for low temperature magnetic refrigeration.

New magnetic states in crystals

The static and resonance properties of copper metaborate CuB2O4 were experimentally studied in a magnetic field applied in the crystal tetragonal plane. The field-induced second-order phase transition to a weakly ferromagnetic state was observed in the temperature range 10–20 K. The low-field state is characterized by the absence of spontaneous moment, and it represents, presumably, a long-period helicoid. At temperatures below 2 K, two sequential first-order phase transitions were observed. They were accompanied by jumps in resonance absorption with a hysteresis upon changing field-scan direction. These transitions can be caused by the transformation of the incommensurate spin structure into the helicoidal states with periods commensurate with the lattice translation period.