Isothermal changes of volume and Young's modulus of amorphous CoP

The isothermal shrinkage and the isothermal increase of Young's modulus E of electrodeposited CoP samples were studied in the amorphous state and during crystallization. The lower limit of the activation spectrum of the elementary processes responsible for these changes is shifted from 0.8 to 1.6 eV by annealing at temperatures ascending from 100°C to 220°C. From the Arrhenius equation a frequency constant of 10^9.5±2.5 was derived.On account of the different behavior of the two properties we conclude that the changes of E in connection with the relaxation of the amorphous structure is mainly a consequence of the homogenization of the material and the shrinkage is mainly a consequence of the annihilation of free volume. Based on the observations a model is proposed concerning the nature of the elementary processes involved in the different steps of structural relaxation. During crystallization the correlation between the increases in Young's modulus and in density is totally removed. These results show that the observation of temporal and thermal changes of only one physical property does not yield full information about the kinetics of structural relaxation and crystallization.