Noise properties of ferromagnetic tunnel junctions
نویسندگان
چکیده
We report measurements of voltage fluctuations in magnetic tunnel junctions which exhibit both high and low magnetoresistance ~MR!. The voltage noise power normalized to the square of the junction bias voltage was 10/Hz at a frequency of 1 Hz in a high MR junction. Low MR junctions had significantly higher noise power at 1 Hz and the origin of the noise was not magnetic. In these junctions, random telegraph noise was observed over a wide range of temperatures and junction biases. The results are consistent with a two-channel model of conduction, one of which is spin independent and gives rise to large noise. A noise measuring technique provides evidence for bias-dependent current-path rearrangements. The data support the existence of an inhomogeneous ~filamentary-like! current-flow pattern across the tunnel junction associated with the spin-independent channel. © 1998 American Institute of Physics. @S0021-8979~98!09023-9#
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تاریخ انتشار 1998