Thermodynamic growth model of single crystal Bi-2212 whisker

► Whiskers growth is related by surface energy change. ► It was found that needle-like grain formation needs higher free energy. ► Evaporation of ions supports whisker formation. In this study the growth mechanism of superconducting Bi-2212 whiskers is investigated from a thermodynamic point of view. The evolution of the free energy of the growth region in the main matrix is evaluated by estimating that of its surface energy. It is shown that the local free energy change for partial melting is the same as that of the whole structure of the sample. It is pointed out that the formation of whiskers requires a higher energy than that of plate like grains.