Magnetoelectric Coupling Effect And Optical Properties Of YIG-P(VDF-TrFE) Multiferroic Composite Films

Multiferroic materials have attracted wide attention of researchers because of its unique magnetoelectric coupling effect and“magneto-electric”double-tuning performance,which can meet the current miniaturization and multi-functionalization,integration and other requirements of the communication devices.In this paper,we have selected the multi-iron system of YIG-P(VDF-TrFE)composite film as the research object,and mainly carried out systematic studies on multiferroic,inverse magnetoelectric coupling effect,microwave magnetic dielectric effect,and optical bandgap by electric field.The following are the main contents of the paper:At first,the multiferroic properties and the magnetoelectric coupling properties of0.4YIG-0.6P(VDF-TrFE)composite film has been characterized.The results show that the composite film has both ferroelectricity and ferromagnetism,which proves that the system has multiferroic properties.The inverse magnetoelectric coupling effect of the composite film was observed.The main mechanism is the stress coupling mechanism within the system.At the same time,the direction of the bias magnetic field will cause the change of the inverse magnetoelectric coupling coefficientα_c(E⊥H is 1.10%,E∥H is 1.59%).The maximum value of the magnetic dielectric effect in the microwave band(10-400 MHz)is MD=3.5%.After analyzing the variation of dielectric constant and dielectric loss with bias magnetic field,it is considered that the magnetic dielectric effect of the composite film is due to the stress coupling mechanism,and the magnetoresistance effect and the"Maxwell-Wagner"effect also contribute to this result.Due to the excellent magneto-optical properties of YIG and its wide application in magneto-optic thin-film devices,the influence of biasing electric field on the optical properties of xYIG-(1-x)P(VDF-TrFE)multiferroic composite films was investigated.The results show that the optical band gap of the composite film will red shift with the increase of the bias electric field(YIG weight ratio x=0.05,0.10,0.20 composite optical band gap at 6MV/m bias electric field variation at 0.11eV,0.13eV,0.17eV).It is considered that there is a ferroelectric phase P(VDF-TrFE)in the system,and its own electro-optic effect causes the optical bandgap of the material to be modulated by the biased electric field.The stress coupling mechanism(magnetoelectric coupling performance)in the system and the Zeeman effect of the ferromagnetic phase YIG also contribute to this result.