Effects of strain relaxation in Pr0.67Sr0.33MnO3 films probed by polarization dependent X-ray absorption near edge structure

Abstract

The Mn K edge X-ray absorption near edge structure (XANES) of Pr0.67Sr0.33MnO3 films with different thicknesses on (001) LaAlO3 substrate was measured, and the effects of strain relaxation on film properties were investigated. The films showed in-plane compressive and out-of-plane tensile strains. Strain relaxation occurred with increasing film thickness, affecting both lattice constant and MnO6 octahedral rotation. In polarization dependent XANES measurements using in-plane (parallel) and out-of-plane (perpendicular) geometries, the different values of absorption resonance energy Er confirmed the film anisotropy. The values of Er along these two directions shifted towards each other with increasing film thickness. Correlating with X-ray diffraction (XRD) results it is suggested that the strain relaxation decreased the local anisotropy and corresponding probability of electronic charge transfer between Mn 3d and O 2p orbitals along the in-plane and out-of-plane directions. The XANES results were used to explain the film-thickness dependent magnetic and transport properties.

Atomic-scale investigation of MgO growth on fused quartz using angle-dependent NEXAFS measurements

“…Further, evolution of this interaction in different directions could be successfully depicted using angle-dependent NEXAFS spectroscopy for organic molecules, 25 oriented ZnO nanostructures, 26 and Pr 0.67 Sr 0.33 -MnO 3 lms. 27 Thus, NEXAFS investigations were extended to angle-dependent measurements in the present study. [28][29][30] In recent years, MgO has attracted more interest due to its unusual magnetism [31][32][33][34] and optical behavior.…”

Tuning Flux Pinning in GdBa2Cu3O7–x/La0.7Sr0.3MnO3 Epitaxial Bilayers via Substrate-Induced Strain

“…The behavior of Mn valence vs thickness is similar to that of the Mn–O bond ratio of the MnO 6 octahedron in Figure d. This result can be ascribed to an enhanced charge transfer between O 2p and Mn 3d orbitals, owing to a large overlap due to the Mn–O bond contraction . Thus, in the case of the L80 sample with strain relaxation, the Mn valence decreases in accordance with an increase of the Mn–O bond.…”

Interfacial Coupling-Induced Ferromagnetic Insulator Phase in Manganite Film

“…We further verify the weak charge transfer across the interface by first-principles calculations (Figure S3). All films were fabricated under the same conditions and the FI′ phase could not have resulted from the oxygen vacancy or different chemical valence, as verified by the Mn K -edge XANES showing the same peak position in the spectra − (Figure S4). Another possible factor is the misfit strain (1.1%) between Pr 0.67 Sr 0.33 MnO 3 and STO that may increase resistivity and decrease the PI-to-FM phase transition ( p 1) temperature in manganite film. , The effect of misfit strain will gradually diminish in thicker film experiencing strain relaxation.…”