Title :
Spin Torque Enhancement of Thermally Excited Ferromagnetic Resonance in Tunneling MR Heads
Author :
Zhu, Jian-Gang ; Zhou, Yuchen ; Mao, Sining
Author_Institution :
Dept. of Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA
Abstract :
In this paper, we present an experimental study on the effect of spin torque to the thermally excited ferromagnetic resonance, known as mag-noise, in tunneling magnetoresistive (TMR) read heads that are currently used in hard disk drive applications. Power spectra densities of the tunnel junction read heads under a dc bias current over a frequency range from 0.5 to 12 GHz are obtained as functions of applied magnetic field and bias current. All the important characteristics of spin torque driven microwave oscillations can be clearly identified in the observed power spectral densities. In contrast to current-perpendicular-to-plane spin valve sensors, no 1/f-like noise below 2 GHz has been observed
Keywords :
ferromagnetic resonance; hard discs; magnetic heads; magnetic multilayers; magnetic recording; magnetic recording noise; spin dynamics; tunnelling magnetoresistance; 0.5 to 12 GHz; 1/f noise; hard disk drive; mag-noise; magnetic field; magnetic tunnel junction; microwave oscillations; power spectral densities; spin torque; spin valve sensors; thermally excited ferromagnetic resonance; tunneling MR heads; tunneling magnetoresistive read heads; Frequency; Hard disks; Magnetic fields; Magnetic heads; Magnetic resonance; Magnetic sensors; Sensor phenomena and characterization; Spin valves; Torque; Tunneling magnetoresistance; Magnetic tunnel junction; magnetic tunnel junction read heads; microwave oscillation; spin momentum transfer; spin torque; spin waves;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2006.878689
