Exchange Bias in Ni-Mn-Sn Heusler Alloy Films
I. Gościańskaa, K. Załęskib, H. Głowińskib, Yu.V. Kudryavtsevc, and J. Dubowikb
aDepartment of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
bInstitute of Molecular Physics, PAS, M. Smoluchowskiego 17, 60-179 Poznań, Poland
cInstitute of Metal Physics, NANU, Vernadsky Ave. 36, Kiev-142, Ukraine
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We report a relatively large exchange bias effect observed for the first time in Ni-Mn-Sn thin films with different microstructure and composition: a Ni50Mn36Sn14 epitaxial film (A), a Ni50Mn43Sn7 film which is phase decomposed (B), and a NiMn/Ni50Mn25Sn25 bilayer (C). Despite the samples differ markedly in both microstructure and composition HEB does not substantially differs at 5 K. Exchange bias decreases with increasing T approximately as HEB (T) ∝ HEB (5 K)/T with HEB (5 K) of 180 Oe and 60 Oe for sample B and C, respectively and almost linearly for sample A with HEB (5 K) = 65 Oe. Blocking temperature where the exchange bias vanishes is 40, 50 and 80 K for sample A, C and B, respectively. The results suggest that the role of AFM/FM interfaces is not substantial in formation of exchange bias in Ni-Mn-Sn Heusler alloy films and exchange bias is rather related to AFM/FM interactions in nanoscale.
DOI: 10.12693/APhysPolA.121.1179
PACS numbers: 75.70.Ak, 75.30.Et