Intrinsic Ferromagnetism and Surface Oxidation in Nb2FeC: Revealed by Synchrotron-Based X-Ray Spectro- and Microscopy
Journal
Advanced Electronic Materials
Series/Report No.
Advanced Electronic Materials
Journal Volume
12
Journal Issue
17
Start Page
e70534
ISSN
2199-160X
Date Issued
2026-09-07
Author(s)
Das, Sambhu Charan
Chen, Kuan‐Hung
Lin, Wei‐Xuan
Wang, Hsiao‐Tsu
Lee, Cheng‐En
Yeh, Ping‐Hung
Zhang, Cheng‐En
Du, Chao‐Hung
Chiou, Jau‐Wern
Tsai, Huang‐Ming
Hsu, Kim
Wang, Chun‐Chieh
Zhou, Jigang
Wang, Jian
Ray, Sekhar Chandra
S. K., Deepak Vishnu
Pong, Way‐Faung
Abstract
A-site substitution in Mn+1AXn (MAX) phases with transition metals carrying partially filled 3d orbitals offers a pathway to induce magnetism in otherwise nonmagnetic layered carbides/nitrides. Here, we investigate Nb2FeC, obtained by replacing the nonmagnetic Al site in Nb2AlC with Fe, using synchrotron-based spectroscopy and microscopy. Structural analysis confirms hexagonal P63/mmc phase with alternating Fe and Nb2C layers along the c-axis. Surface-sensitive X-ray absorption reveals a thin Fe-oxide overlayer from ambient exposure, while Fe in the bulk reveals alloying-driven hybridization between Fe and Nb states. Magnetization measurements establish robust ferromagnetism with a Curie temperature near 283 K. Importantly, Fe L3,2-edge Scanning Transmission X-ray Microscopy (STXM) combined with X-ray Magnetic Circular Dichroism (XMCD) directly demonstrates intrinsic bulk ferromagnetism, even though conventional surface-sensitive XMCD shows no signal. The STXM-XMCD dichroic response remains nearly unchanged across regions of varying thickness, indicating that ferromagnetic (FM) correlations are confined within the two-dimensional Fe layers and coupled only weakly across Nb2C spacers. Thickness-dependent absorption spectra further reveal Fe─Nb hybridization, underscoring the role of A-site substitution in tuning magnetic interactions. These findings identify Nb2FeC as a rare/near room-temperature FM MAX phase and highlight A-site engineering as a versatile strategy for designing layered magnetic carbides for spintronic applications.
Subjects
MAX phase
scanning transmission X-ray microscopy
X-ray absorption spectroscopy
X-ray magnetic circular dichroism
Publisher
Wiley
Type
journal article