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Emergent Interfacial Ferromagnetism and Exchange Bias Effect in Paramagnetic/Ferromagnetic Oxide Heterostructures
Author(s) -
Bhatt Harsh,
Kumar Yogesh,
Prajapat Champa Lal,
Kinane Christy J.,
Caruana Andrew,
Langridge Sean,
Basu Saibal,
Singh Surendra
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202001172
Subject(s) - ferromagnetism , materials science , condensed matter physics , lanio , heterojunction , exchange bias , paramagnetism , magnetization , neutron reflectometry , magnetism , antiferromagnetism , magnetic anisotropy , neutron , optoelectronics , neutron scattering , physics , magnetic field , ferroelectricity , quantum mechanics , dielectric , small angle neutron scattering
The experimental evidence of the exchange bias (EB) effect in epitaxial heterostructures of ferromagnetic La 0.67 Sr 0.33 MnO 3 (LSMO) and paramagnetic LaNiO 3 (LNO) grown on MgO(001) substrates is reported. The macroscopic magnetization measurements show a clear indication of EB in LNO/LSMO and LSMO/LNO/LSMO heterostructures. The strength of the exchange coupling rapidly reduces as the temperature is increased and almost vanishes above 50 K. Using spin dependent polarized neutron reflectometry (PNR) detailed depth dependent magnetization profiles of the heterostructures are investigated to understand the role of interface magnetism in the observed EB. PNR results establish the emergence of the interfacial ferromagnetic LNO layer of thickness ≈22–35 Å (≈6–9 unit cell) and magnetization ≈80 emu cc −1 at the LNO/LSMO interface for T < 100 K. The PNR results also show both ferromagnetic and anti‐ferromagnetic coupling between the LSMO and interfacial LNO layers, which may be dependent on the stacking order. The emergence of ferromagnetism in the interfacial paramagnetic LNO layer with unexpected EB in these heterostructures suggests a promising platform toward the effective realization of magnetic devices.