Coercivity change in an FePt thin layer in a Hall device by voltage application

Abstract

The coercivity (Hc) of a perpendicularly magnetized FePt layer was modulated by applying the voltage (Vapp) to a Hall device through MgO and Al–O insulating layers. A change in ∼40 Oe in Hc was observed by changing Vapp from −13 to 13 V. From the quantitative analysis of the voltage effect on Hc, the change in the anisotropy energy by voltage application was evaluated to be 18.6 fJ/V m, which was of the same order as the theoretical prediction. The role of the MgO layer for the voltage effect was also discussed.

Electric-field control of magnetic domain-wall velocity in ultrathin cobalt with perpendicular magnetization

“…Electric-field control of coercivity 25, DW propagation 27, magnetic anisotropy 29 (magnetization direction), and magnetization 31 have also been reported. More recently, similar effects have been observed even in ferromagnetic metals at room temperature 30,[32][33][34]36,37 , and these effects are attracting much attention owing to their potential use in practical applications.…”

“…The anomalous Hall effect was used to detect the local magnetization direction in the vicinity of the Hall probes 22,[24][25][26][27]32,[34][35][36][37] . The Hall resistance R Hall , which is proportional to the perpendicular component of the magnetization M, was measured under an external magnetic field H applied perpendicularly to the Co film (see Methods for the details of the transport measurement).…”

“…Current-induced DW motion is of particular interest because it enables the position of DW to be controlled electrically without applying an external magnetic field [1][2][3][4][7][8][9][10][11][12][13][14][16][17][18][19][20][21] . The electric field effect on magnetic materials has been actively studied recently, because magnetic properties can be controlled electrically [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] , when a field-effect-device structurethat is, one consisting of a top-gate electrode, a dielectric insulator layer (or a liquid electrolyte), and a ferromagnetic layer-is used to modulate a carrier density. The first reported magnetic phase transition induced by the electric field was one in a ferromagnetic semiconductor 22 .…”

Ferroelectric control of magnetic domains in ultra-thin cobalt layers

“…[5][6][7][8][9] In such layers, a delicate balance between different contributions to the magnetic anisotropy energy (MAE) results in their high sensitivity to the changes of electronic structure at the interface. 10 Thus, a weak change of charge density induced by the electric field at the extremely narrow interface-adjacent layer is sufficient for a substantial change of coercivity, 5-7 T C , 8,9 and magnetic domain kinetics.…”

Role of CoFeB thickness in electric field controlled sub-100 nm sized magnetic tunnel junctions

“…[10][11][12] One of the alternative low power writing schemes in MTJs is by means of voltage controlled magnetic anisotropy (VCMA). [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Write energies as low as 6 fJ/bit has been demonstrated using this scheme. 25,29 In this work, by incorporating Ta/CoFeB/MgO as the free layer in pMTJs, we investigatei) CoFeB thickness dependent VCMA at the single domain limit using sub-100 nm MTJs and ii) consequence of thickness dependence on the precessional magnetization switching.…”