Electrocaloric effect anomaly in multiferroic BiFeO3

Electrocaloric Effect of multiferroic BiFeO3 (BFO) has been studied by using the method of Green's function. The calculations demonstrate that the isothermal entropy change (IEC) of BFO exhibits a cusp-like structure at ferromagnetic transition temperature T-N. This anomaly in IEC can be explained as the effect of magnetic order disappearance above T-N. Note that a maximum IEC appears at the temperature of T-0, which is coincide with the ferroelectric transition temperature T-C. Besides, the IEC increases slightly with the anisotropy constant K-D increase in the vicinity of T-N. At last but not least, the IECs decrease with the ferroelectric interaction (I) and the magnetoelectric coupling constant (g) increase, whereas the T-N shift to higher temperature with the I and the g increase. Those conclusions drawn are in good accordance with the experimental results and other theory findings.