Sv. Lubenets et al., INFLUENCE OF THE OXYGEN-CONTENT ON THE MI CROHARDNESS OF YBA2CU3O7-DELTA SINGLE-CRYSTALS IN THE TEMPERATURE-RANGE 77-293 K, Fizika nizkih temperatur, 21(3), 1995, pp. 324-330
The concentration dependence of the microhardness H-nu(delta) of the s
ingle crystals YBa2Cu3O7-delta of two types has been studied in the te
mperature range 77-293 K. It has been found that the microhardness inc
reases linearly with decreasing temperature and the temperature depend
ence of H-nu(T) is the stronger the less oxygen content. An analysis o
f the results obtained shows that such H-nu(delta, T) behavior is defi
ned not by changing the elastic properties of the crystals but by the
effect of oxygen concentration and oxygen vacancies ordering on the co
re structure and dislocations mobility which realize plastic deformati
on in the vicinity of an indentation.