Strain-mediated magnetoelectric control of tunneling magnetoresistance in magnetic tunneling junction/ferroelectric hybrid structures

【摘要】 Because of the wide selectivity of ferromagnetic and ferroelectric（FE） components,electric-field（E-field） control of magnetism via strain mediation can be easily realized through composite multiferroic heterostructures.Here,an MgObased magnetic tunnel junction（MTJ） is chosen rationally as the ferromagnetic constitution and a high-activity（001）-Pb(Mg_1/3Nb_2/3)_0.7Ti_0.3O₃（PMN-0.3 PT） single crystal is selected as the FE component to create a multiferroic MTJ/FE hybrid structure.The shape of tunneling magnetoresistance（TMR） versus in situ E-fields imprints the butterfly loop of the piezo-strain of the FE without magnetic-field bias.The E-field-controlled change in the TMR ratio is up to-0.27%without magnetic-field bias.Moreover,when a typical magnetic field（～± 10 Oe） is applied along the minor axis of the MTJ,the butterfly loop is changed significantly by the E-fields relative to that without magnetic-field bias.This suggests that the E-field-controlled junction resistance is spin-dependent and correlated with magnetization switching in the free layer of the MTJ.In addition,based on such a multiferroic heterostructure,a strain-gauge factor up to approximately 40 is achieved,which decreases further with a sign change from positive to negative with increasing magnetic fields.This multiferroic hybrid structure is a promising avenue to control TMR through E-fields in low-power-consumption spintronic and straintronic devices at room temperature.更多还原

【Abstract】 Because of the wide selectivity of ferromagnetic and ferroelectric（FE） components,electric-field（E-field） control of magnetism via strain mediation can be easily realized through composite multiferroic heterostructures.Here,an MgObased magnetic tunnel junction（MTJ） is chosen rationally as the ferromagnetic constitution and a high-activity（001）-Pb(Mg_1/3Nb_2/3)_0.7Ti_0.3O₃（PMN-0.3 PT） single crystal is selected as the FE component to create a multiferroic MTJ/FE hybrid structure.The shape of tunneling magnetoresistance（TMR） versus in situ E-fields imprints the butterfly loop of the piezo-strain of the FE without magnetic-field bias.The E-field-controlled change in the TMR ratio is up to-0.27%without magnetic-field bias.Moreover,when a typical magnetic field（～± 10 Oe） is applied along the minor axis of the MTJ,the butterfly loop is changed significantly by the E-fields relative to that without magnetic-field bias.This suggests that the E-field-controlled junction resistance is spin-dependent and correlated with magnetization switching in the free layer of the MTJ.In addition,based on such a multiferroic heterostructure,a strain-gauge factor up to approximately 40 is achieved,which decreases further with a sign change from positive to negative with increasing magnetic fields.This multiferroic hybrid structure is a promising avenue to control TMR through E-fields in low-power-consumption spintronic and straintronic devices at room temperature.更多还原