Magnetoelectric properties of CoFe_2O_4-BaTiO_3 core-shell structure composite studied by a magnetic pulse method

摘要

A new method using a magnetic pulse field in order to measure the ME effect of CoFe_2O_4-BaTiO_3 core-shell structure composite has been developed. This new method combines advantages of both quasi-static and dynamic ones and allows quantifying the whole ME response of the materials. The maximum ME coefficient of this composite is 5.5 and 4.2 mV/cm Oe for longitudinal and transverse measurements, respectively. These values are bigger than those measured by the lock-in technique and can be attributed to the fact that the pulse field method determines the full magnetoelectric coefficient whereas the AC method determines only the part that corresponds to the amplitude of the AC field. Both pulse duration and field sweep rate dH/dt are found to affect the ME response of the composite.