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Coercivity variations at the top and bottom NiFe layers in NiFe/FeMn/NiFe trilayers
Author(s) -
Sankaranarayanan V. K.,
Yoon SangMin,
Kim CheolGi,
Kim ChongOh,
Lee Heebok
Publication year - 2004
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200304616
Subject(s) - coercivity , materials science , antiferromagnetism , layer (electronics) , hysteresis , condensed matter physics , anisotropy , composite material , optics , physics
Coercivity variations in the NiFe/FeMn/NiFe trilayer are investigated when the thickness of the bottom and top NiFe layers is increased systematically from 2 nm to 20 nm. The trilayer shows two hysteresis loops corresponding to the two NiFe layers. When the thickness of the bottom seed NiFe layer is increased from 2 nm, after initial high values around 20–30 Oe in the 2–4 nm thickness range, the coercivity of both the loops fall steadily till 10 nm thickness. Thereafter the coercivity for the top NiFe layer shows a sharp increase in the 10–20 nm thickness range. In the case of top NiFe layer thickness variation, the peak in coercivity is observed in the 2–5 nm thickness range. For NiFe thickness of 2 nm in the case of top NiFe thickness variation, and above 10 nm thickness for seed NiFe layer thickness variation, unusually large coercivities are observed. We find that the top NiFe which forms the pinned layer shows greater coercivity in the case of both the top and bottom NiFe thickness variations. Coercivity variations are discussed on the basis of different populations of AFM (antiferromagnet) domains with differing anisotropy energy at the two NiFe/FeMn interfaces. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)