HEAT CAPACITY OF [V.sub.1-x][Fe.sub.x][O.sub.2]-SOLID SOLUTIONS AT HELIUM TEMPERATURES AND THEIR EVOLUTION DURING THERMAL CYCLING

The results of investigations of heat capacity Cp of a series of [V.sub.1- x][Fe.sub.x][O.sub.2]-solid solutions at the temperatures from 4.2 to 25 K are reported. It is found out that at these temperatures considerable contributions into the heat capacity come from the crystal lattice proper and crystal lattice defects formed in the course of material synthesis. The results of investigating the evolution of these materials during thermal cycling are also reported. Keywords: heat capacity, solid solutions, thermal cycling, crystal lattice, crystal lattice defects.