Comment on "Exchange bias-like phenomenon in SrRuO₃" [Appl. Phys. Lett. 88, 102502 (2006)]

Exchange bias, a well known phenomenon encountered in systems containing interfaces between ferromagnetic and antiferromagnetic materials is analyzed. The observation in ferromagnetic-antiferromagnetic systems exhibiting exchange bias is shift of the magnetization hysteresis loops along the field axis while no shift is observed along the magnetization axis. After the field cooling of SrRuO₃ from above the Curie temperature there is no shift in the hysteresis loops and the shift is along the magnetization axis. As a result of irreversible nature of the magnetization process, any ferromagnetic material after being cooled from above Curie temperature will exhibit minor hysteresis loops whose counter is shifted in the magnetization axis.