Studies Of Magnetism Induced By Electric Field In Multiferroic Heterostructure

Accompanied by the emergence of the Third Scientific and Technological Revolution and the rapid development of modern science and technology,multiferroic materials used in high-performance magnetic devices show small size,store fast and high precision,which is widely used in microwave communication systems,information storage systems,electromagnetic interference technology and other fields.Multiferroic materials behave two or more kinds of ferroic orders,such as ferroelectricity,ferromagnetism and ferroelasticity,and it is important to understand and manipulate the magnetism of multiferroic materials in magneto-electric coupling.Due to the ME effect of fast,low-power mode of operation,multiferroic materials systems are commonly used in the manufacture of sensors,multi-state memories and other spin electronics.For the magnetic film used in microwave,the electromagnetic parameters and complex permeability of magnetic materials become the main content and have a very important significance.According to the differences of materials and structure of th magnetic thin film,the magnetic film can be divided into ferrite,perovskite,monolithic metal alloys and metal/oxide films.In this article we mainly research the static,dynamic magnetization and magnetic coupling effects in FeCo/PMN-PT multiferroic heterostructure and magnetic nanocomposites.The remanence of FeCo/Ta multilayers in multiferroic heterostructure is studied in information storage Applications.FeCo/PMN-PT multiferroic heterostructure with different thickness of magnetic thin film was prepared by changing the preparation technology on the PMN-PT(011)substrate by RF magnetron sputtering technique.Researching the influence of the preparation technology for magnetism of multiferroic heterostructure.At the same time ues the vector network analyzer(E5071C)by the transmission line perturbation method to test changes of the S parameter of the entire test device port in order to reverse the sample microwave electromagnetic parameters,by studying the coercivity field,magnetic anisotropy and natural resonance frequency of magnetic thin film samples,it is found that the relationship between the initial natural resonance frequency and the coercivity of the magnetic thin film,and found that the control of the magnetic anisotropy of the magnetic material from 2320e to 420Oe,resulting in a sample with a natural resonant frequency drift from 2.96 GHz to 4 GHz.It is also found that the magnetization reversal cotrolled by electric field in magnetic film which is related to the change of the magnetic domain structure in the film.We prepared FeCo/PMN-PT and[FeCo(9m)/Ta(4nm)]5/PMN-PT on PMN-PT(001)substrate by using magnetron sputtering.We measured the Mr of these heterostructures under different electric field.We found that the four-state change of Mr in FeCo/PMN-PT and[FeCo(9m)/Ta(4nm)]5/PMN-PT heterostructures.However.the four-state performance is unstable and hard to distinguish.So we measured the Mr in[FeCo(9m)/Ta(4nm)]5/PMN-PT heterostructure,and we found the change of four-state of Mr is stable and easy to distinguish.At the same time,we also measured the Mr-E and S-E curves,and explained the physical mechanism of the strain-mediated magnetoelectric coupling effect.This provides important theoretical and technical support for high-density,high capacity information storage.We prepared FeCo/FeMn/Ta/PMN-PT?FeGa/FeMn/Ta/PMN-PT multilayer on PMN-PT(001)substrate by using magnetron sputtering.We researched that the exchange bias field and the magnetoelectric properties in the ferromagnetic/antiferromagnetic structure.It is found that the FeMn anti ferromagnetic layer acts as a pinned layer behaves different on the pinning effect of the two samples.This is because at the interface,the unpaired magnetic moments in the antiferromagnetic layer are sufficiently large relative to the FeGa layer and not sufficiently large for the FeCo layer.The exchange bias phenomenon was observed in the FeGa/FeMn system,and only the change in coercivity was observed in FeCo/FeMn system.