Effect of thermal stress on magnetic domain patterns of multiferroic Bi1-xDyxFeO3 thin films

Effect of temperature on magnetic domain structure of Bi_0.7Dy_0.3FeO₃ (BDFO) multiferroic thin films is studied in situ using magnetic force microscopy (MFM). Initially, as the temperature increases the domains start aligning from irregular to more distinct stripe pattern. However, above 250 °C, the domain alignment is disturbed. The systematic change in the domain configuration with temperature, suggests a strong thermal history of the system. The randomness in domain alignment caused above 250 °C is correlated to internal stress developed during ferromagnetic to paramagnetic phase transition occurring in BDFO. Indirect experimental evidence is given to support the explanation based on stress.