Ultra-high frequency tunability in low-current and low-field spin-torque oscillators based on perpendicular magnetic tunnel junctions

• We demonstrate ultra-high frequency tunability of up to 4.4 GHz/mA, and low threshold currents of about -21 $\mu$A, in spin-torque oscillators based on CoFeB/MgO/CoFeB magnetic tunnel junctions, in which both free and fixed layers have perpendicular magnetic anisotropy (PMA). By using different thicknesses of the two CoFeB layers, their individual PMA strengths can be tailored to achieve significant relative misalignment of their respective magnetizations in moderate in-plane fields. We observe a broad maximum in both the device resistance and the generated microwave power around maximum misalignment. Maximum frequency tunability is observed at low-to-moderate fields and decrease rapidly after maximum misalignment.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Keyword

spin-torque oscillator

magnetic tunnel junction

magnetic perpendicular anisotropy

Materials Science and Engineering

Teknisk materialvetenskap

Physics

Fysik

Publication and Content Type

pop (subject category)

ovr (subject category)