Valuable information about minority point defects in binary oxides can be obtained by using fast temperature (T) and oxygen partial pressure (Po2) changes during high temperature creep deformation. A creep transient is established after a T or Po2change, which reflects the evolution of the point defect concentration responsible for the diffusion of the slowest species to the new equilibrium value, allowing us the determination of the chemical diffusion coefficient and the migration energy of these defects.