On Strain-Mediated Magnetoelectric Effects in Multiferroic Composite Nanostructures

Author:   Haitao Chen ,  陈海涛
Publisher:   Open Dissertation Press
ISBN:  

9781361000465


Publication Date:   26 January 2017
Format:   Paperback
Availability:   Temporarily unavailable   Availability explained
The supplier advises that this item is temporarily unavailable. It will be ordered for you and placed on backorder. Once it does come back in stock, we will ship it out to you.

Our Price $129.36 Quantity:  
Add to Cart

Share |

On Strain-Mediated Magnetoelectric Effects in Multiferroic Composite Nanostructures


Add your own review!

Overview

This dissertation, On Strain-mediated Magnetoelectric Effects in Multiferroic Composite Nanostructures by Haitao, Chen, 陈海涛, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Multiferroics which combine two or more order parameters of ferroelectricity, ferromagnetism and ferroelasticity, have drawn great interests in the past few years due to their promising potential of application in sensors, transducers, spintronics and multistate memories. Coupling between the ferroelectricity and ferromagnetism renders the induction of an electric polarization P upon applying a magnetic field, or the induction of a magnetization M upon applying an electric field which is called magnetoelectric coupling effect. There are single phase multiferroics which simultaneously possess ferroelectricity and magnetism in nature. However, these natural multiferroics only exhibit weak magnetoelectric coupling effect at very low temperature which hinders the practical applications. An alternative and more promising choice is to fabricate multiferroic composites. In the multiferroic composite systems, large magnetoelectric coupling effects can be produced indirectly from the strain-mediated interaction even at room temperature and great design flexibility can be obtained. In the present study, two types of multiferroic composite nanostructures are investigated: the vertical heteroepitaxial multiferroic thin films and film-on-substrate heterogeneous bilayers with incorporation of various influences, such as film thickness, misfit strains and flexoelectricity. Since the first fabrication of vertical epitaxial multiferroic nanostructures, great scientific interests have been attracted for the potential large magnetoelectric effects arising from the relaxed substrate constraint and large interfacial area between the ferroelectric and ferromagnetic phases. A three dimensional phase field model is devised to precisely describe the complex strain state of this nanostructure. The simulation results demonstrate that both film thickness and misfit strains are important in determining the magnitude of magnetoelectric effect. Due to the strong strain-mediated magnetoelectric coupling effect in film-on-substrate system with a ferromagnetic thin film directly growing on a thick ferroelectric substrate, precision electric control of local ferromagnetism, i.e. ferromagnetic domain pattern and domain wall properties, are achievable. The results show that the domain pattern of the ferroelectric substrate can be fully transferred onto the as-deposited ferromagnetic thin film. High stability of the magnetic domain is observed when the system is subjected to an external magnetic field. Under an applied electric field, the transferred domain pattern in magnetic film can be either maintained or erased depending on the direction of applied electric field. Moreover, when a pulse of in-plane electric field is applied, the magnetic domain wall motion can be observed in concurrence with the ferroelectric domain wall motion. With the decrease of material size, some effects that can be neglected in bulk materials may play an important role on the overall properties of material, such as flexoelectric effects which describe the induction of polarization from strain gradient. A two dimensional phase field model is adopted to study the influence of flexoelectric effects on the epitaxial ferroelectric films. A thermodynamic phenomenological model is then utilized to analyze the influence of flexoelectric effects on magnetic field induced electric polarization in the multiferroic nanocomposite b

Full Product Details

Author:   Haitao Chen ,  陈海涛
Publisher:   Open Dissertation Press
Imprint:   Open Dissertation Press
Dimensions:   Width: 21.60cm , Height: 0.80cm , Length: 27.90cm
Weight:   0.363kg
ISBN:  

9781361000465


ISBN 10:   1361000465
Publication Date:   26 January 2017
Audience:   General/trade ,  General
Format:   Paperback
Publisher's Status:   Active
Availability:   Temporarily unavailable   Availability explained
The supplier advises that this item is temporarily unavailable. It will be ordered for you and placed on backorder. Once it does come back in stock, we will ship it out to you.

Table of Contents

Reviews

Author Information

Tab Content 6

Author Website:  

Customer Reviews

Recent Reviews

No review item found!

Add your own review!

Countries Available

All regions
Latest Reading Guide

Aorrng

Shopping Cart
Your cart is empty
Shopping cart
Mailing List