Thickness-Dependent Magnetism in Epitaxial SrFeO<sub>3-δ</sub> Thin Films

Palakkal, Jasnamol P.; Zeinar, Lukas; Major, M.; Komissinskiy, Philipp; Schneider, Thorsten; Alff, Lambert

doi:10.1109/tmag.2020.3023372

Cited by 3 publications

(1 citation statement)

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“…Such a lattice-locking effect limits strain relaxation by lattice rearrangement. This effect is dramatic when the thickness of films is less than 50 nm and weakened for thick films . The differences in the thermal expansion coefficient can also introduce residual strain during the fabrication processes. ,, Our recent research shows that strontium molybdate (SrMoO 3 ) has a tunable strain-dependent permittivity crossover point .…”

Section: Introductionmentioning

confidence: 99%

Crystalline AuNP-Decorated Strontium Niobate Thin Films: Strain-Controlled AuNP Morphologies and Optical Properties for Plasmonic Applications

Yao

Berenov

Bower

et al. 2023

ACS Appl. Nano Mater.

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Gold nanoparticle (AuNP) decoration is a commonly used method to enhance the optical responses in many applications such as photocatalysis, biosensing, solar cells, etc. The morphology and structure of AuNPs are essential factors determining the functionality of the sample. However, tailoring the growth mechanism of AuNPs on an identical surface is not straightforward. In this study, AuNPs were deposited on the surface of a perovskite thin film, strontium niobate (SNO), using pulsed laser deposition (PLD). AuNPs exhibited a dramatic variation in their growth mechanisms, depending on whether they were deposited on SNO thin films grown on magnesium oxide (SNO/MgO) or strontium titanate (SNO/STO) substrates. On SNO/MgO, the Au aggregates form large NPs with an average size of up to 3500 nm2. These AuNPs are triangular with sharp edges and corners. The out-of-plane direction of growth is favored, and the surface coverage ratio by AuNPs is low. When deposited on SNO/STO, the average size of AuNPs is much smaller, i.e., ∼250 nm2. This reduction in the average size is accompanied by an increase in the number density of NPs. AuNPs on SNO/STO have a round shape and high coverage ratio. Such an impact from the substrate selection on the AuNP structure is significant when the sandwiched SNO film is below 80 nm thickness and is weakened for 200 nm of SNO films. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize all samples. Strain analysis was used to explain the growth mechanism of AuNPs. The average height of AuNPs was measured by using atomic force microscopy (AFM). Ellipsometry in the visible–near-infrared (vis–NIR) region was used to characterize the optical response of all samples. AuNP-decorated SNO/MgO and SNO/STO thin films exhibit different optical properties, with only gold-decorated SNO/MgO samples showing a size-dependent epsilon-near-zero behavior of nanoparticles. These results provide an additional route to control the structure of AuNPs. They can be used for various plasmonic applications like the design and development of strain-engineered gold-nanoparticle-decorated devices for surface-enhanced Raman spectroscopy (SERS) and photocatalysis.

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Section: Introductionmentioning

confidence: 99%

Crystalline AuNP-Decorated Strontium Niobate Thin Films: Strain-Controlled AuNP Morphologies and Optical Properties for Plasmonic Applications

Yao

Berenov

Bower

et al. 2023

ACS Appl. Nano Mater.

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Functional double perovskites from bulk to thin film heterostructures: The example of La2NiMnO6

Palakkal¹,

Alff

2023

Perovskite Ceramics

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Oxygen defect engineered magnetism of La2NiMnO6 thin films

2022

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The double perovskite La2NiMnO6 (LNMO) exhibits complex magnetism due to the competition of magnetic interactions that are strongly affected by structural and magnetic inhomogeneities. In this work, we study the effect of oxygen annealing on the structure and magnetism of epitaxial thin films grown by pulsed laser deposition. The key observations are that a longer annealing time leads to a reduction of saturation magnetization and an enhancement in the ferromagnetic transition temperature. We explain these results based upon epitaxial strain and oxygen defect engineering. The oxygen enrichment by annealing caused a decrease in the volume of the perovskite lattice. This increased the epitaxial strain of the films that are in-plane locked to the SrTiO3 substrate. The enhanced strain caused a reduction in the saturation magnetization due to randomly distributed anti-site defects. The reduced oxygen defects concentration in the films due to the annealing in oxygen improved the ferromagnetic long-range interaction and caused an increase in the magnetic transition temperature.

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Thickness-Dependent Magnetism in Epitaxial SrFeO_3-δ Thin Films

Cited by 3 publications

References 36 publications

Crystalline AuNP-Decorated Strontium Niobate Thin Films: Strain-Controlled AuNP Morphologies and Optical Properties for Plasmonic Applications

Crystalline AuNP-Decorated Strontium Niobate Thin Films: Strain-Controlled AuNP Morphologies and Optical Properties for Plasmonic Applications

Functional double perovskites from bulk to thin film heterostructures: The example of La2NiMnO6

Oxygen defect engineered magnetism of La2NiMnO6 thin films

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Thickness-Dependent Magnetism in Epitaxial SrFeO3-δ Thin Films

Cited by 3 publications

References 36 publications

Crystalline AuNP-Decorated Strontium Niobate Thin Films: Strain-Controlled AuNP Morphologies and Optical Properties for Plasmonic Applications

Crystalline AuNP-Decorated Strontium Niobate Thin Films: Strain-Controlled AuNP Morphologies and Optical Properties for Plasmonic Applications

Functional double perovskites from bulk to thin film heterostructures: The example of La2NiMnO6

Oxygen defect engineered magnetism of La2NiMnO6 thin films

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Thickness-Dependent Magnetism in Epitaxial SrFeO_3-δ Thin Films