Tunable random telegraph noise in individual square permalloy dots

Daniel E. Endean, C. T. Weigelt, R. H. Victora, E. Dan Dahlberg

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Magnetization fluctuations caused by thermal energies are poorly understood, yet they represent a fundamental limit for many magnetic technologies. Here, thermal fluctuations of the magnetization are quantitatively characterized. The model magnetic system is thin square magnetic dots (<10nm) with side lengths down to 200 nm. The magnetic state and the fluctuations are determined in individual dots by measuring the anisotropic magnetoresistance. The magnetization exhibits random telegraph noise with a transition rate determined by the dot size, the applied magnetic field, and the sample temperature. An energy barrier model of the system explains the dependence of the magnetic fluctuations on these parameters and is supported by additional experiments unaffected by the magnetic fluctuations. This independent identification of the mechanism producing magnetic noise, and its agreement with micromagnetic simulations, demonstrates a microscopic understanding of noise extendable to more complex noise sources such as 1/f noise.

Original languageEnglish (US)
Article number252408
JournalApplied Physics Letters
Issue number25
StatePublished - Jun 23 2014

Bibliographical note

Publisher Copyright:
© 2014 AIP Publishing LLC.


Dive into the research topics of 'Tunable random telegraph noise in individual square permalloy dots'. Together they form a unique fingerprint.

Cite this