TY - JOUR
T1 - A large unidirectional magnetoresistance in Fe-Sn heterostructure devices
AU - Shiogai, Junichi
AU - Fujiwara, Kohei
AU - Nojima, Tsutomu
AU - Tsukazaki, Atsushi
N1 - Funding Information:
This work was partly supported by CREST (No. JPMJCR18T2) the Japan Science and Technology Agency, and TEPCO Memorial Foundation. The device fabrication was partly performed at Cooperative Research and Development Center for Advanced Materials under the GIMRT Program of the Institute for Materials Research, Tohoku University (Proposal No. 202012-CRKEQ-0410). We thank NEOARK Corporation for the photolithography process.
Publisher Copyright:
© 2022 The Japan Society of Applied Physics.
PY - 2022/8/1
Y1 - 2022/8/1
N2 - Unidirectional magnetoresistance (UMR) is an attractive magnetic-field sensing technique as it enables us to detect the in-plane direction of the external magnetic field with a single element. However, the UMR amplitude is typically several orders of magnitude smaller than those of other directional magnetoresistances exhibited in ferromagnetic thin films, hindering sensing applications using the UMR. For a directional magnetic sensor using the UMR, an in-depth understanding of the mechanisms of the UMR and its enhancement are highly desirable. In this study, the structural dependence of the UMR in Fe-Sn heterostructure devices is investigated. We find a weak dependence of the UMR on interface configuration in the oxide cap/Fe-Sn heterostructures on various oxide substrates. In contrast, the normalized UMR amplitude is enhanced by a factor of 27 with increasing Fe-Sn layer thickness from 4.0 to 100 nm. These results suggest that the magnetothermal effect dominates the large UMR in the Fe-Sn heterostructure devices.
AB - Unidirectional magnetoresistance (UMR) is an attractive magnetic-field sensing technique as it enables us to detect the in-plane direction of the external magnetic field with a single element. However, the UMR amplitude is typically several orders of magnitude smaller than those of other directional magnetoresistances exhibited in ferromagnetic thin films, hindering sensing applications using the UMR. For a directional magnetic sensor using the UMR, an in-depth understanding of the mechanisms of the UMR and its enhancement are highly desirable. In this study, the structural dependence of the UMR in Fe-Sn heterostructure devices is investigated. We find a weak dependence of the UMR on interface configuration in the oxide cap/Fe-Sn heterostructures on various oxide substrates. In contrast, the normalized UMR amplitude is enhanced by a factor of 27 with increasing Fe-Sn layer thickness from 4.0 to 100 nm. These results suggest that the magnetothermal effect dominates the large UMR in the Fe-Sn heterostructure devices.
KW - anomalous Nernst effect
KW - magnetic sensor
KW - unidirectional magnetoresistance
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U2 - 10.35848/1347-4065/ac7bc8
DO - 10.35848/1347-4065/ac7bc8
M3 - Article
AN - SCOPUS:85135371705
SN - 0021-4922
VL - 61
JO - Japanese Journal of Applied Physics
JF - Japanese Journal of Applied Physics
IS - 8
M1 - 083001
ER -