Magnetoelectric Zn0.2Co0.8Fe2O4-PbZr0.58Ti0.42O3 nanocomposite for bistable memory and magnetic field sensor applications

The spinel ferrite based nanocomposite (Zn0.2Co0.8Fe2O4-PbZr0.58Ti0.42O3) has been prepared through a chemical process to observe the magnetoelectric and memory effect at room temperature. The structural and surface characterization of the nanoparticles reveal the presence of both the phases having crystallites size in nanometric regime, which are uniformly distributed. The observed nonlinear behaviour of the current of magnetic field dependent current-voltage characteristic may be due to the oxygen vacancy and defect states at the grain boundaries of the granular system. The sharp increased in nature of current is attributed to the space charge polarization and the space charge limited current determining through Child's law. The maximum value of current is found to similar to 60 mu A in presence of 15 V at similar to 2 kOe. Moreover, the change of open circuit current is found to similar to 71% in magnetic field. The DC electrical property of the nanocomposite shows two separate resistance states. Furthermore, the magnetic field dependent resistance is varying with an applied electric field and viceversa. These features are a demonstration of good magnetoelectric coupling between the piezoelectric and piezomagnetic order parameters. The magnetoelectric coupling coefficient of the nanocomposite may be attributed to the magnetostriction properties of the piezomagnetic phase. The magnetoelectric coupling coefficient is largely depending on the direction of an applied magnetic field for the directional dependent magnetostriction properties of the piezomagnetic phase. The maximum value of the coupling coefficient has been found to similar to 4.5 mV/cm-Oe at room temperature. Furthermore, an applied AC magnetic field dependent magnetoelectric voltage coefficients of the nanocomposite have been estimated, which is completely matched with an observed value. This nanocomposite demonstrates the presence of memory effect, resistive switching behaviour, magnetoelectric coupling, etc.