Enhanced tunnel magnetoresistance and electric-field effect in CoFeB/MgO/CoFeB perpendicular tunnel junctions with W underlayer

• Published in: Current applied physics Vol. 17; no. 7; pp. 962 - 965
• Main Authors: Kim, Dae-Hoon, Park, Kyung-Woong, Park, Byong-Guk
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2017; 한국물리학회
• Subjects: Electric-field effect; Magnetic tunnel junction; Perpendicular magnetic anisotropy; Tunnel magnetoresistance; 물리학; Electric-field effect; Tunnel magnetoresistance; Perpendicular magnetic anisotropy; Magnetic tunnel junction
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2017.04.003

We investigated the dependence of tunnel magnetoresistance (TMR) and its electric-field effect in CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJ) on different underlayer (UL) materials. We observed enhancements in the TMR ratio and its temperature dependence as well as electric-field effect in MTJs with W UL, as compared to those in MTJs with a conventional Ta UL. This is attributed to better thermal stability of perpendicular magnetic anisotropy (PMA) in W/CoFeB/MgO, which sustains up to 380 °C, compared to that of Ta/CoFeB/MgO which starts to degrade at 270 °C. This demonstrates that the PMA in a CoFeB/MgO structure and its electric-field dependence can be enhanced by the careful selection of underlayer, opening the way for the realization of electric-field effect-driven spintronic devices.
•We study underlayer effect in CoFeB/MgO/CoFeB magnetic tunnel junction.•Magnetoresistance and its electric-field effect are enhanced by W underlayer.•Proper selection of underlayer materials can improve spintronic device performances.