Strain-mediated voltage control of magnetism in multiferroic Ni77Fe23/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 heterostructure

Abstract

Using voltage-modified anisotropic magnetoresistance (AMR) measurement, we demonstrated a strain-mediated voltage control of magnetism in multiferroic Ni77Fe23(NiFe, 10 nm)/Pb (Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT, bulk crystal) heterostructure, even assuming a very small magnetostriction (∼0.3 ppm) for the NiFe film which has a composition close to bulk permalloy (Ni80Fe20). Influence of the magnitude of the rotating magnetic field used for AMR tests is studied. Combined AMR and theoretical analysis indicate the voltage-modified change in the magnetoresistance of the NiFe film arises from the reduced free energy barrier between the magnetic easy axis and hard axis via voltage-induced strains in the PMN-PT.

Electric field modification of magnetotransport in Ni thin films on (011) PMN-PT piezosubstrates

“…For all the cases, the maximum AMR values are similar, varying between 2.31% and 2.62%, and being just slightly smaller than $3% observed for a Ni 77 Fe 23 /PMN-PT heterostructure. 17 The effect of the electric field pulse application is mainly reflected in the modification of the anisotropy field H a (marked in Fig. 3(b) by dashed lines) when the magnetization is aligned with the applied magnetic field.…”

“…13,14 Permalloy exhibits, however, a small magnetoelastic coupling constant, while its study on PMN-PT was made available only at finite magnetic fields. 17 Moreover, to be useful for a device, one needs a change of the resistance at zero applied voltage, which has not been demonstrated using the application-relevant electrical readout. Furthermore, for 3d-metals, Ni exhibits the highest magnetoelastic coupling and is thus the material of choice where, by determining the full field dependence of the magnetotransport properties, one can gauge the applicability of this approach.…”

“…2 There are numerous reports on voltage control of magnetization (see, e.g., reviews, 1-4 references therein, and recent Refs. 5 11), whereas for electric field effects on the anisotropic [12][13][14][15][16][17][18][19][20] and giant 13,21,22 [4][5][6][7][8][9][10][11]13,14,16,17,20 In such structures, upon application of an electric field, the piezoactive substrate induces a strain in the ferro(i)magnetic film and hence modifies its magnetic properties due to the magnetoelastic coupling effect. The (011) cut is particularly suitable because of the possibility of obtaining a high and well-defined uniaxial anisotropy by inducing simultaneously compressive and tensile strains in orthogonal [100] (x) and [011] (y) in-plane directions due to the different signs of d 31 and d 32 piezocoefficients.…”

Magnetically correlated anisotropic resistive switching manipulated by electric field in Co/PMN-PT heterostructures

“…The electric-field-controlled reversible magnetization rotation, which is important for practical applications in a wide range of low-power magnetic and spintronic devices [1,12], has been reported in Ni/0.7Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 [8,10,23] (Ni/PMN-PT) and CoFeB/PMN-PT [24] as well as the phase field simulations [8,12]. These magnetization rotations should naturally affect the electronic transport behaviors in the magnetic films [25][26][27][28]. Because the magnetization orientation in 3d-alloy films gives rise to the in-plane anisotropic resistivity owing to the spin-orbit interaction [29], the magnetization rotations can induce the variations of anisotropic magnetoresistivity (AMR) in magnetic films such as Fe 4 N [25,27], NiFe [26,28],…”

Solving the electrical control of magnetic coercive field paradox

“…We demonstrated that the strain mediated magneto-electric coupling 36,37 significantly alters the effective magneto-crystalline anisotropy field of magnetic grains when they are coupled to a piezo-electric active material.…”