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

QC 20160829
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.

Eklund, Anders,1986-KTH,Integrerade komponenter och kretsar(Swepub:kth)u1ds4vid (författare)
Banuazizi, Seyed Amir HosseinKTH,Materialfysik, MF(Swepub:kth)u1db6muw (författare)
Chung, SunjaeKTH,Materialfysik, MF,Univ Gothenburg, Sweden(Swepub:kth)u1htqp0u (författare)
Fallahi, Vahid FallahiFaculty of Physics, Amirkabir University of Technology (författare)
Nguyen, Thi Ngoc AnhKTH,Materialfysik, MF(Swepub:kth)PI000000 (författare)
Yamanouchi, M.Laboratory for Nanoelectronics and Spintronics, RIEC, Tohoku University (författare)
Enobio, Eli C. I.Center for Spintronics Integrated Systems, Tohoku University (författare)
Ikeda, S.Laboratory for Nanoelectronics and Spintronics, RIEC, Tohoku University (författare)
Ohno, HideoLaboratory for Nanoelectronics and Spintronics, RIEC, Tohoku University (författare)
Åkerman, JohanKTH,Materialfysik, MF,Univ Gothenburg, Sweden; NanOsc AB, Sweden(Swepub:kth)u13m1xx2 (författare)
KTHMaterialfysik, MF (creator_code:org_t)

Av författaren/redakt...: Le, Quang Tuan, ...; Eklund, Anders, ...; Banuazizi, Seyed ...; Chung, Sunjae; Fallahi, Vahid F ...; Nguyen, Thi Ngoc ...; visa fler...; Yamanouchi, M.; Enobio, Eli C. I ...; Ikeda, S.; Ohno, Hideo; Åkerman, Johan; visa färre...

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