Tunable linear magnetoresistance in MgO magnetic tunnel junction sensors using two pinned CoFeB electrodes

J. Y. Chen, J. F. Feng, J. M.D. Coey

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

MgO-barrier magnetic tunnel junction sensors with both CoFeB layers pinned by IrMn have been fabricated, which show a tunneling magnetoresistance (TMR) of up to 255% at room temperature. The perpendicular configuration for magnetic field sensing is set using a two-step field annealing process. The linear TMR field range and sensitivity are tuned by inserting an ultrathin Ru layer between the upper IrMn and the top-pinned CoFeB layer. The field sensitivity reaches 26%/mT, while the noise detectivity is about 90 nT/ √Hz at 10 Hz for a 0.3 nm Ru insertion layer. The bias dependence of the noise suggests that this is a useful design for sensor applications.

Original languageEnglish (US)
Article number142407
JournalApplied Physics Letters
Volume100
Issue number14
DOIs
StatePublished - Apr 2 2012

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