Multiferroics simultaneously exhibit several order parameters such as ferroelectricity and antiferromagnetism,representing an appealing class of multifunctional material.As the only multiferroics above room temperature,BiFeO_3(BFO) becomes an attractive choice for a wide variety of applications in the areas of sensors and spintronic devices.The coexistence of several order parameters brings about novel physical phenomena,for example,the magnetoelectric coupling effect.It allows the reversal of ferroelectric...