Quantitative Evaluation of Voltage-Induced Magnetic Anisotropy Change by Magnetoresistance Measurement

We investigated the voltage-induced perpendicular magnetic anisotropy change in an epitaxial magnetic tunnel junction (MTJ) with an ultrathin FeCo layer. Tunneling magnetoresistance (TMR) curves were measured under various bias voltage applications for different FeCo thicknesses. Clear changes in th...

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Bibliographic Details
Published inApplied physics express Vol. 4; no. 4; pp. 043005 - 043005-3
Main Authors Shiota, Yoichi, Murakami, Shinichi, Bonell, Frédéric, Nozaki, Takayuki, Shinjo, Teruya, Suzuki, Yoshishige
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.04.2011
IOPScience - Japan Society of Applied Physics
Subjects
Physics
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Summary:We investigated the voltage-induced perpendicular magnetic anisotropy change in an epitaxial magnetic tunnel junction (MTJ) with an ultrathin FeCo layer. Tunneling magnetoresistance (TMR) curves were measured under various bias voltage applications for different FeCo thicknesses. Clear changes in the shape of TMR curves were observed depending on the voltage-controlled perpendicular magnetic anisotropy. By evaluating the relative angle of two ferromagnetic layers, we could estimate the anisotropy energy change quantitatively. The realization of voltage-induced anisotropy change in the MTJ structure makes it possible to control the magnetization dynamics, leading to a new area of electric-field-based spintronics devices.
Bibliography:TMR curves of the MTJs with $t_{\text{FeCo}}=0.68$, 0.63, and 0.60 nm measured under the magnetic field (a)--(c) in-plane (hard axis) directions or (d)--(f) perpendicular to the film plane. Bias voltage dependence of the normalized TMR curves of (a) $t_{\text{FeCo}}=0.68$ nm, and (b) $t_{\text{FeCo}}=0.60$ nm. Only the positive magnetic field region is shown here. The perpendicular anisotropy energy, $E_{\text{perp}}$, was estimated from the shaded area shown in the inset. The bottom figures represent the magnetization configuration of two ferromagnetic layers at zero magnetic field, and the direction of the external magnetic field. Applied electric-field dependence of the surface magnetic anisotropy energy, $E_{\text{perp}}t_{\text{FeCo}}$, calculated from the TMR curves. (a) $t_{\text{FeCo}}=0.68$ nm and (b) $t_{\text{FeCo}}=0.60$ nm. The lines are a guided for the eye.
ISSN:1882-0778
1882-0786
1882-0786
DOI:10.1143/APEX.4.043005