Electric-Field Control of Nonvolatile Magnetization in ${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}/\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}{)}_{0.7}{\mathrm{Ti}}_{0.3}{\mathrm{O}}_3$ Structure at Room Temperature

We report a large and nonvolatile bipolar-electric-field-controlled magnetization at room temperature in a ${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}/\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}{)}_{0.7}{\mathrm{Ti}}_{0.3}{\mathrm{O}}_3$ structure, which exhibits an electric-field-controlled looplike magnetization. Investigations on the ferroelectric domains and crystal structures with in situ electric fields reveal that the effect is related to the combined action of 109° ferroelastic domain switching and the absence of magnetocrystalline anisotropy in ${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}$. This work provides a route to realize large and nonvolatile magnetoelectric coupling at room temperature and is significant for applications.

Figure 1

(a) Scheme of the sample and experimental configuration. (b) In-plane magnetic hysteresis loops under electric fields of $+8\mathrm{kV}{\mathrm{cm}}^{-1}$ (circle) and $-8\mathrm{kV}{\mathrm{cm}}^{-1}$ (square). (c) Electric-field tuning of the in-plane magnetization (square) and polarization current (open circle) recorded at the same time. (d) The repeatable high/low magnetization states (open circle) switched by pulsed electric fields (blue line).

Figure 2

(a), (d), and (g) are the out-of-plane phase PFM images while (b), (e), and (h) are the in-plane ones. Corresponding to PFM images in the upper panel, the sketch maps (c), (f), and (i) show the different configurations of the polarization vector under different voltages, where the long arrows along the body diagonals represent the spontaneous polarization vectors in the rhombohedral phase and short arrows in the center of cubic represent the out-of-plane polarization components, respectively. The broad arrows along the diagonals of the top square stand for the in-plane polarization components and their colors correspond to those in the in-plane PFM images (b), (e), and (h).

Figure 3

(a) to (d) show the electric-field tuned XRD-RSMs around the (113) reflection. Ellipses with different colors in the RSMs draw the outlines of the deduced spots with center positions listed in Table S1. (e) Configuration of the (113) crystal face (translucent blue plane) and the rhombohedral distortions as well as polarizations shown by the arrows, whose colors correspond to the colors of the ellipses in (a) to (d). (f) The 109° switching induced changes of in-plane distortions along the [110] direction as well as the corresponding lattice parameters and the in-plane projections of polarization vectors (broad arrows).