Electric-field control of local ferromagnetism using a magnetoelectric multiferroic

Abstract

Multiferroics are of interest for memory and logic device applications, as the coupling between ferroelectric and magnetic properties enables the dynamic interaction between these order parameters. Here, we report an approach to control and switch local ferromagnetism with an electric field using multiferroics. We use two types of electromagnetic coupling phenomenon that are manifested in heterostructures consisting of a ferromagnet in intimate contact with the multiferroic BiFeO(3). The first is an internal, magnetoelectric coupling between antiferromagnetism and ferroelectricity in the BiFeO(3) film that leads to electric-field control of the antiferromagnetic order. The second is based on exchange interactions at the interface between a ferromagnet (Co(0.9)Fe(0.1)) and the antiferromagnet. We have discovered a one-to-one mapping of the ferroelectric and ferromagnetic domains, mediated by the colinear coupling between the magnetization in the ferromagnet and the projection of the antiferromagnetic order in the multiferroic. Our preliminary experiments reveal the possibility to locally control ferromagnetism with an electric field.

Regular nanodomain vertex arrays in BiFeO3single crystals

“…We have to parenthetically mention here that the surface of BiFeO 3 , and especially the domain structure at the surface, proved to play an essential role in the exchange bias coupling between BiFeO 3 and adjacent magnetic layers. 15 When judging the properties of domains and domain walls in multiferroic materials, the orientation (habit plane) of the domain wall in relation to the polarization direction has to be carefully considered. 16,17 This is the reason why we not only report on the observation of a new type of nanodomain in BiFeO 3 single crystals by transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM), the shape and arrangement of which correspond to a linear arrangement of vertices, but also strive to analyze the geometry and orientation of the domain walls in some detail.…”

Experimental Demonstration of Complete 180° Reversal of Magnetization in Isolated Co Nanomagnets on a PMN–PT Substrate with Voltage Generated Strain

“…Popular approaches include passing a spin current through the soft layer to generate a spin transfer torque [2][3][4][5][6][7] or spin orbit torque [8][9][10][11] or domain wall motion [12][13] . Other approaches involve using voltage controlled magnetic anisotropy 14 , magnetoelectric effects [15][16][17] , magnetoionic effects 18 and magnetoelastic effects [19][20][21][22][23][24][25] . Unfortunately, generation of a spin current requires passing a charge current through a resistor that dissipates excessive energy, making the spin-current based schemes relatively energy-inefficient 26,27 .…”

Magnetoelectric coupling across the interface of multiferroic nanocomposites

“…In 2008, Mathur [74] had demonstrated that the magnetic domain structures could be controlled by applying electric field in the multiferroic BFO-based heterostructures. Chu et al [75] and Heron et al [76] took CoFe alloy as the ferromagnetic layer to construct a coupling between ferromagnetism and antiferromagnetism in BFO/ CoFe. Using XMCD-photo emission electron microscopy (PEEM) and piezoresponse force microscopy (PFM), Chu found that the magnetic domain structures of CoFe were coupled with the ferroelectric domains and the antiferromagnetic easy plane of BFO.…”