Inducing high resonant frequency in exchange-coupled bilayer via fast annealing
Abstract
The reversed magnetization of NiFe (10 nm)/FeMn (8 nm) bilayers was carried out in an applied external magnetic field (Ha) with the direction opposite to the deposition magnetic field (Hd). The exchange bias field (He) , static magnetic anisotropic field (Hksta), and resonant frequency (fr) of the bilayers before and after annealing were characterized. Part of the AFM moments were fixed at an opposite direction to another part by controlling the capacitor voltage. At the critical capacitor voltages 37 and 43 V, the AFM moments and corresponding FM moments in Ha direction were almost the same as in Hd direction, respectively, and were responsible for the lower Hksta and He . This demonstrates that the strongest competitive effect between the AFM/FM exchange coupled with opposite direction, and thus more unstable AFM grains occurred, causing the rotational anisotropy field (Hrot), fr , and the dynamic magnetic anisotropic field (Hkdyn) to reach their maximum.
- Publication:
-
Physica B Condensed Matter
- Pub Date:
- March 2020
- DOI:
- 10.1016/j.physb.2019.411948
- Bibcode:
- 2020PhyB..58011948W
- Keywords:
-
- Pulsed current;
- Fast annealing;
- Resonant frequency;
- Exchange bias