Options
The role of epitaxial strain on the electronic and magnetic structure of La0.7Sr0.3MnO3/LaCoO3 bilayers
Citation
Das, S., Ghosh, S., Tanguturi, R. G., Medwal, R., Gupta, S., Dokala, R. K., Rawat, R. S., Das, S., & Thota, S. (2021). The role of epitaxial strain on the electronic and magnetic structure of La0.7Sr0.3MnO3/LaCoO3 bilayers. AIP Advances, 11, Article 125115. https://doi.org/10.1063/5.0071572
Author
Das, Shaona
•
Ghosh, Sayandeep
•
Tanguturi, Ranganadha Gopalarao
•
Medwal, Rohit
•
Gupta, Surbhi
•
Dokala, Ravi Kiran
•
•
Das, Sujit
•
Thota, Subhash
Abstract
Realizing atomically flat interfaces between the ultrathin perovskite oxides is a challenging task, which usually possess different chemical environments, depending on the terminating lattice planes. Hence, tuning the interfaces across the heterostructures for desired electrical and magnetic properties is a powerful approach in oxide electronics. Focusing on these aspects, in the present work we employ a novel strategy of engineering the interfaces through the layer stacking sequence and degree of strain to probe the changes occurring in the local atomic environment at the interfaces, magnetic behaviour, and electronic properties of ferromagnetic bilayers La0.7Sr0.3MnO3 (LSMO)/LaCoO3 (LCO) grown by the pulsed laser deposition technique. The biaxial tensile strain experienced by these layers drives the ferromagnetic (FM) ordering temperatures to lower values as compared to their bulk counterparts. Interestingly, the bilayer sequence LCO (15 nm)/LSMO (5 nm) (BL2) exhibits large magnetocrystalline anisotropy (Ku ≈ 4.7 × 104 erg/cc) and weak anti-FM coupling across the interface of the two FM constituents, resulting in a partial compensation in the magnetic moment of the system within a specific temperature window (ΔT = 184 − 82 K). However, for T ≤ 82 K, the FM superexchange interaction between the trivalent Co high-spin and low-spin states dominates the overall magnetic ordering in BL2. The magnetodynamic features probed by the frequency dependent FM resonance (FMR) on this system yield the gyromagnetic ratio (γ/2π ∼ 29.22 GHz/T), demagnetization fields (4πMeff ∼ 3770 Oe), and effective damping constant (αeff ∼ 0.0143) for the BL2 configuration. Moreover, the strength of the nearest-neighbor exchange interaction Jeff in the BL2 configuration exhibits linear falloff with the increasing LCO layer thickness (2 nm ≤𝑡𝐿𝐶𝑂≤ 18 nm). This scenario is also consistent with the variation of the effective number of spins available per unit volume [10 cm−3 ≤ NV(×1022) ≤ 2 cm−3] with increasing tLCO. As tLCO approaches negligibly small values (<2 nm), the magnitude of Jeff/kB reaches its maximum ∼5.47 K (for LCO) and 21.93 K (for LSMO), which is in good agreement with Jeff/kB ∼ 5 ± 2 K (20 ± 2 K) for highly epitaxial LCO (LSMO) single layers. These results demonstrate that the layer sequence control of magnetic coupling across the interfaces opens a constructive approach for exploring the novel electronic devices
Publisher
American Institute of Physics
Journal
AIP Advances
Project
ARC 1/19 RSR
NRF-CRP21-2018-0003
Grant ID
SR/FST/PSII-020/2 009
SR/FST/PSII-037/2 016)
Funding Agency
Department of Science
and Technology, India
and Technology, India
Central Instrument Facility (CIF) of the Indian
Institute of Technology Guwahati
Institute of Technology Guwahati
Council
of Scientific and Industrial Research (CSIR), Ministry of Science and
Technology, the Ministry of Education, Government of India
of Scientific and Industrial Research (CSIR), Ministry of Science and
Technology, the Ministry of Education, Government of India
Ministry of Education, Singapore
National Research Foundation, Singapore