Spin conduction and interfacial effects in La2/3Sr1/3MnO3/NiO/Pt heterostructures
Chen, Shoulong (Institut de Ciència de Materials de Barcelona)
Pomar, Alberto (Institut de Ciència de Materials de Barcelona)
Balcells Argemí, Lluís (Institut de Ciència de Materials de Barcelona)
Konstantinovic, Zorica (University of Belgrade)
Frontera, Carlos (Institut de Ciència de Materials de Barcelona)
Magen Dominguez, Cesar (Instituto de Nanociencia de Aragón)
Mestres i Andreu, Narcís (Institut de Ciència de Materials de Barcelona)
Martínez, Benjamín (Institut de Ciència de Materials de Barcelona)

Date:	2025
Abstract:	In this work we report on the generation and transport of pure spin currents in LaSrMnO(LSMO)/NiO/Pt heterostructures. Pure spin currents, generated by means of spin pumping in the LSMO layer, are transmitted through the NiO layer and detected by measuring the transverse voltage signal generated by the inverse spin Hall effect (ISHE) in the Pt layer. The spin current transmission is studied as a function of the NiO thickness and temperature. NiO layers grown at room temperature are polycrystalline and their microstructural and magnetic features clearly depend on thickness. Scanning transmission electron microscopy techniques revealed that homogeneous conformal coating of the LSMO layer is only achieved for NiO layer thicknesses above about 2 nm. Below this critical thickness the NiO layer is discontinuous and its main role would be to disturb the LSMO/Pt interface causing it to behave as something similar to an insulating barrier. Magnetic measurements indicate that NiO layers are paramagnetic (PM) well below room temperature. In agreement with these observations, the amplitude of the ISHE voltage signal decreases monotonically on lowering temperature and makes evident that there are two spin conduction regimes as a function of the NiO layer thickness with different spin diffusion lengths. For thin discontinuous NiO layers a spin diffusion length of λ≈0. 8 nm is found, which is slightly larger than typical values found for insulating barriers, but definitely smaller than λ≈3. 8 nm found for NiO layer thickness above 2 nm. The latter being similar to λ previously reported for epitaxial NiO layers. Our findings indicate that inserting a PM NiO insulating layer of optimal thickness improves the spin transparency of the LSMO/Pt interface. Additionally, the results suggest that spin conduction through the NiO layer is likely driven by magnetic correlations and short-range thermal magnons.
Grants:	Ministerio de Ciencia, Innovación y Universidades CEX2023-001263-S Agencia Estatal de Investigación PID2021-128410OB-I00 Agencia Estatal de Investigación PID2020-112914RB-I00 Agencia Estatal de Investigación PID2021-124680OB-I00
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Published in:	Journal of alloys and compounds, Vol. 1010 (January 2025) , art. 177453, ISSN 0925-8388

DOI: 10.1016/j.jallcom.2024.177453

Available from: 2027-01-31 Postprint

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