This book mainly focuses on the investigation of the electric-field control of magnetism and spin-dependent transportation based on a Co40Fe40B20(CoFeB)/Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) multiferroic heterostructure. Methods of characterization and analysis of the multiferroic properties with in situ electric fields are induced to detect the direct magnetoelectric (ME) coupling. A switchable and non-volatile electric field control of magnetization in CoFeB/PMN-PT(001) structures is observed at room temperature, and the mechanism of direct coupling between the ferroelectric domain and ferromagnetic film due to the combined action of 109° ferroelastic domain switching in PMN-PT and the absence of magnetocrystalline anisotropy in CoFeB is demonstrated. Moreover, the electric-field control of giant magnetoresistance is achieved in a CoFeB-based spin valve deposited on top of (011) oriented PMN-PT, which offers an avenue for implementing electric-writing and magnetic-reading random access memory at room temperature. Readers will learn the basic properties of multiferroic materials, many useful techniques related to characterizing multiferroics and the interesting ME effect in CoFeB/PMN-PT structures, which is significant for applications.
Sen Zhang received his B.Sc. in physics from School of Physical Science and Technology, Lanzhou University, China in 2007. He obtained his Ph.D. in physics from Physics Department of Tsinghua University in June 2012. His major research project in Prof. Yonggang Zhao's group is preparing compounded multiferroic structures as well as spintronic devices and studying on electric field control of magnetization as well as electronic transport in ferromagnetic/ferroelectric heterostructures. He is now a lecturer at College of Science, National University of Defense Technology, focusing on the coupling effect of electric, magnetic and photonic properties in nanomaterial and nanostructures.
Introduction.- Experimental Methods.- Electric-field control of Magnetism in CoFeB/PMN-PT(001) Structure.- Electric-Field Control of Magnetism and Magnetoresistance in CoFeB/PMN-PT(011) Structure.- Summary and Outlook.