Nanoscale magnetic and charge anisotropies at manganite interfaces

CARREIRA, SANTIAGO J.; AGUIRRE, MYRIAM H.; BRIATICO, JAVIER; STEREN, LAURA B.

RSC Advances

Royal Society of Chemistry

Año: 2019 vol. 9 p. 38604 - 38611

Strong correlated manganites are still under intense research owing to their complex phase diagrams interms of Sr-doping and their sensitivity to intrinsic and extrinsic structural deformations. Here, weperformed X-ray absorption spectroscopy measurements of manganite bilayers to explore the effectsthat a local Sr-doping gradient produce on the charge and antiferromagnetic anisotropies. In order togradually tune the Sr-doping level along the axis perpendicular to the samples we have grown a series ofbilayers with different thicknesses of low-doped manganites (from 0 nm to 6 nm) deposited overa La0.7Sr0.3MnO3 metallic layer. This strategy permitted us to resolve with high accuracy the thicknessregion where the charge and spin anisotropies vary and the critical thickness tc over which the out ofplane orbital asymmetry does not have any further modifications. We found that the antiferromagneticspin axis points preferentially out of the sample plane regardless the capping layer thickness. However, ittilts partially into the sample plane far from this critical thickness, owing to the combined contributionsof the external structural strain and electron doping. Furthermore, we found that the doping level of thecapping layer strongly affects the critical thickness, giving clear evidence of the influence exerted by theelectron doping on the orbital and magnetic configurations. These anisotropic changes induce subtlemodifications on the domain reorientation of La0.7Sr0.3MnO3, as evidenced from the magnetic hysteresiscycles.