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Microstructures and Interface Magnetic Moments in Mn2VAl/Fe Layered Films Showing Exchange Bias

Authors :
Takahide Kubota
Yusuke Shimada
Tomoki Tsuchiya
Tomoki Yoshikawa
Keita Ito
Yukiharu Takeda
Yuji Saitoh
Toyohiko J. Konno
Akio Kimura
Koki Takanashi
Source :
Nanomaterials, Vol 11, Iss 7, p 1723 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

Heusler alloys are a material class exhibiting various magnetic properties, including antiferromagnetism. A typical application of antiferromagnets is exchange bias that is a shift of the magnetization curve observed in a layered structure consisting of antiferromagnetic and ferromagnetic films. In this study, a layered sample consisting of a Heusler alloy, Mn2VAl and a ferromagnet, Fe, is selected as a material system exhibiting exchange bias. Although the fully ordered Mn2VAl is known as a ferrimagnet, with an optimum fabrication condition for the Mn2VAl layer, the Mn2VAl/Fe layered structure exhibits exchange bias. The appearance of the antiferromagnetic property in the Mn2VAl is remarkable; however, the details have been unclear. To clarify the microscopic aspects on the crystal structures and magnetic moments around the Mn2VAl/Fe interface, cross-sectional scanning transmission electron microscope (STEM) observation, and synchrotron soft X-ray magnetic circular dichroism (XMCD) measurements were employed. The high-angle annular dark-field STEM images demonstrated clusters of Mn2VAl with the L21 phase distributed only around the interface to the Fe layer in the sample showing the exchange bias. Furthermore, antiferromagnetic coupling between the Mn- and Fe-moments were observed in element-specific hysteresis loops measured using the XMCD. The locally ordered L21 phase and antiferromagnetic Mn-moments in the Mn2VAl were suggested as important factors for the exchange bias.

Details

Language :
English
ISSN :
20794991
Volume :
11
Issue :
7
Database :
Directory of Open Access Journals
Journal :
Nanomaterials
Publication Type :
Academic Journal
Accession number :
edsdoj.2279de7f47994f4e97d7c94ef99bcb70
Document Type :
article
Full Text :
https://doi.org/10.3390/nano11071723