Giant room-temperature modulation of magnetic anisotropy by electric fields in CoFeB/(011)-PMN-PT multiferroic heterostructures with two distinct initial magnetic anisotropies

What is it about?

This paper reports that the in-situ growth magnetic field (Hg) during magnetic-phase CoFeB deposition impacts the electric-field control of magnetic anisotropy in Co40Fe40B20/(011)-Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (CoFeB/(011)-PMN-PT) composite multiferroic heterostructures at room temperature. In the Hg1 mode (in-situ Hg along the [01"1" ̅] direction of the ferroelectric PMN-PT substrate), the electric-field-controlled modulation ratios of the magnetic coercivity Hc and saturation magnetic field Hs are approximately -47% and +156%, respectively. However, in the Hg2 mode (in-situ Hg along the [100] direction of the ferroelectric PMN-PT substrate) of the CoFeB/(011)-PMN-PT multiferroic heterostructure, the electric-field-controlled modulation ratios of the magnetic coercivity Hc and saturation magnetic field Hs can reach as high as +162% and +393%, respectively. Moreover, the electric-field-controlled magnetic coercive field Hc exhibits a butterfly shape when plotted versus the applied electric fields in both modes, which matches the in-plane butterfly strain loop of the ferroelectric PMN-PT substrate. However, the electric-field-controlled saturation magnetic field Hs presents a square loop, which is very consistent with the ferroelectric loop of the PMN-PT substrate. This result may be ascribed to the distinct pathway of the ferroelastic domain switching in the (011)-oriented PMN-PT substrate. This study provides a new idea for the design of spintronic devices based on multiferroic heterostructure.

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Photo by Gavin Allanwood on Unsplash

Photo by Gavin Allanwood on Unsplash

Why is it important?

This work reports the in-situ growth magnetic field (Hg) during magnetic-phase CoFeB deposition impacts the electric-field control of magnetic anisotropy in Co40Fe40B20/(011)-Pb(Mg1/3Nb2/3)0.7Ti0.3O3 multiferroic heterostructures. This has not been systematically reported in the composite multiferroic heterostructures. We have achieved giant electric-field-controlled modulation ratios of the magnetic coercivity HC and effective magnetic anisotropy HK approximately -47% and +156% in the Hg1 mode. In the Hg2 mode, the electric-field-controlled modulation ratios of HC and HK can reach as high as +162% and +393%, respectively. Such a giant and different electric-field-controlled magnetic behavior is ascribed to the initial magnetic anisotropy and strain-mediated magnetoelectric coupling.