Magnetoelectric coupling effect of polarization regulation in BiFeO_(3)/LaTiO_(3)heterostructures

An effective regulation of the magnetism and interface of ferromagnetic materials is not only of great scientific significance,but also has an urgent need in modern industry.In this work,by using the first-principles calculations,we demonstrate an effective approach to achieve non-volatile electrical control of ferromagnets,which proves this idea in multiferroic heterostructures of ferromagnetic La TiO_(3)and ferroelectric Bi FeO_(3).The results show that the magnetic properties and two-dimensional electron gas concentrations of La TiO_(3)films can be controlled by changing the polarization directions of Bi FeO_(3).The destroyed symmetry being introduced by ferroelectric polarization of the system leads to the transfer and reconstruction of the Ti-3 d electrons,which is the fundamental reason for the changing of magnetic properties.This multiferroic heterostructures will pave the way for non-volatile electrical control of ferromagnets and have potential applications.

Thermodynamic assessment of Mg-Ni-Y system focusing on long-period stacking ordered phases in the Mg-rich corner

The long-period stacking ordered phases(LPSOs) in Mg-Ni-Y system have been attracting great interest as effective strengthening components because of their unique structural characteristics and deformation mechanism.However,the phase relationships in LPSOs are complicated and unclear,which restricts the design of advanced magnesium-based alloys.The aim of the present work is to experimentally determine the phase equilibria relationships focusing on LPSOs and establish the thermodynamic description for Mg-Ni-Y system.Four types of LPSOs,that is,14H,12R,18R and 10H,are confirmed through equilibrated alloys and high-resolution transmission electron microscopy(HR-TEM).The formation enthalpies of LPSOs(14H,12R,18R and 10H) are calculated based on density functional theories(DFT) calculations.A new ternary compound,termed as τ phase,is observed for the first time which is likely to be the distorted structure of 12R as determined from the TEM image which shows a 12-layer closed packing plane distance of 3.252nm and a shear angle of 83.2°between(0002) and(10■0) planes.Based on the determined phase equilibria relationship,the Mg-Ni-Y system is assessed and a selfconsistent description is obtained where the LPSOs are modeled as the stoichiometric compounds.The comparison between the calculation result and experimental data suggests the accuracy of the present thermodynamic database in the Mg-rich corner.