Onset of magnetic interface exchange interactions in epitaxially grown Mn/Co(001)

Abstract

Manganese (Mn) grows in a metastable expanded (c/a > 1) face-centered-tetragonal (fct) phase on thin fct-Co(001) template films. A layer-by-layer growth mode is observed for small Mn thicknesses. Antiferromagnetism (AFM) of fct-Mn is evidenced by the observation of shifted magnetization loops antiparallel to the cooling field direction (negative bias) and enhanced coercive fields for Co/Mn bilayers. At low temperature, magnetic exchange interactions are detected at the Co/Mn interface for nominal Mn thicknesses as low as 1.4 monolayer (ML), indicating the onset of AFM in 2-ML-thick Mn islands. However, between 2- and 5-ML Mn, a positive bias of the magnetization loops is observed in a certain temperature range below the blocking temperature (TB) of the films. This peculiar behavior is explained by the dependence of TB on both the local Mn ML thickness and the Mn island size, leading to a unidirectional coercivity enhancement in a temperature range where both blocked and unblocked regions coexist in the Mn layers.

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Correspondence to J. T. Kohlhepp.

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This paper was selected as the Outstanding Meeting Paper for the 2006 MRS Spring Meeting Symposium Q Proceedings, Vol. 941E. DOI: 10.1557/JMR.2007.0074

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Kohlhepp, J.T., Wieldraaijer, H. & de Jonge, W.J.M. Onset of magnetic interface exchange interactions in epitaxially grown Mn/Co(001). Journal of Materials Research 22, 569–572 (2007). https://doi.org/10.1557/jmr.2007.0074

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