Noise in magnetic tunnel junction devices
2003; American Institute of Physics; Volume: 93; Issue: 10 Linguagem: Inglês
10.1063/1.1557764
ISSN1520-8850
AutoresK.B. Klaassen, J.C.L. van Peppen, X. Xing,
Tópico(s)Magnetic properties of thin films
ResumoThe noise expected from an ideal magnetic tunnel junction (MTJ) head is thermal noise at low bias voltages (≪50 mV, thermally assisted barrier crossings) and shot noise at higher bias voltages (≫50 mV, field-assisted barrier crossings). The shot noise is larger than the thermal noise, therefore, at 200 mV, the signal of an MTJ head has to be a factor of 2 larger than that of a GMR head with the same resistance to realize the same SNR. This paper reports MTJ noise measurements up to the ferromagnetic resonance (1–2 GHz). An ultra low-noise pre-amplifier system is described that allows electrical biasing of the devices. Wide-band 1/f noise is observed in devices without proper hard bias. Saturation is used to assess the magnetic fluctuation noise and the resonance therein. These wide-band noise measurements demonstrate that one can electronically read out MTJ heads up to the ferromagnetic resonance and down to the noise floor.
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