Charge transfer-induced magnetic exchange bias and electron localization in (111)- and (001)-oriented LaNiO3/LaMnO3 superlattices

Abstract

High-quality lattice-matched LaNiO3/LaMnO3 superlattices with monolayer terrace structure have been grown on both (111)- and (001)-oriented SrTiO3 substrates by pulsed laser deposition. In contrast to the previously reported experiments, a magnetic exchange bias is observed that reproducibly occurs in both (111)- and (001)-oriented superlattices with the thin single layers of 5 and 7 unit cells, respectively. The exchange bias is theoretically explained by charge transfer-induced magnetic moments at Ni atoms. Furthermore, magnetization data at low temperature suggest two magnetic phases in the superlattices, with Néel temperature around 10 K. Electrical transport measurements reveal a metal-insulator transition with strong localization of electrons in the superlattices with the thin LaNiO3 layers of 4 unit cells, in which the electrical transport is dominated by two-dimensional variable range hopping.

Low-temperature anomalous spin correlations and Kondo effect in ferromagnetic SrRuO3/LaNiO3/La0.7Sr0.3MnO3Ghosh1, Tanguturi2, Pramanik3 et al. 2019Phys. Rev. B15060View full textAdd to dashboardCite

“…S3 of supplementary data), whereas, TL2 (001) sample displays the metallic behaviour with metal-insulator transition (T MI ) around T ∼ 200 K. On the other hand, all other samples show completely metallic behaviour for different (LSMO and SRO) thicknesses. Such higher order of magnitude in the electrical resistivity was reported in the literature with decreasing thickness of the film in monolayers and heterostructures of LSMO and SRO [65][66][67] . The metallic behaviour increases progressively with increasing the externally applied magnetic field.…”

The Exchange Bias of LaMnO3/LaNiO3 Superlattices Grown along Different Orientations

“…have recently indicated the absence of exchange bias in the relatively thick LMO/LNO superlattice along (001) orientation is due to charge transfer being suppressed by orbital reconstruction 13 . In addition, it was found that the exchange bias can be observed in thin LMO/LNO superlattice along the (001) direction 14 . However, these remarkable findings indicate that information required to analyze the relationship between exchange bias effect and various orientations of LMO/LNO superlattices is still lacking.…”

Study of Electronic States in LaNiO3/SrRuO3 Bilayers: Interface‐Induced Magnetism and Charge Transfer

“…[8] Superlattices of [LaNiO 3 /LaMnO 3 ] grown along [111] orientation behaved like the FM insulator double perovskite La 2 MnNiO 6 . [9][10][11] Magnetic frustration and spin glass behavior are other features observed in LNO-based multilayers. [12,13] In LSMO/LNO multilayers, oxygen vacancies, interdiffusion of cation and/or charge across the interface, variation of the valence state, etc.…”