We investigate spin-orbit torque effects in epitaxial ${\text{La}}_{0.67}{\text{Sr}}_{0.33}{\text{MnO}}_3$ (LSMO) films via spin-torque ferromagnetic resonance. In the absence of any extrinsic spin source, spin currents with ${\sigma }_y, {\sigma }_z$, and ${\sigma }_x$ polarizations are observed in a single LSMO layer. Decomposing the response within the Kubo linear response formalism reveals that the ${\sigma }_y$ component is composed of both interband and intraband terms, whereas the ${\sigma }_z$ and ${\sigma }_x$ components are dominated by the interband term. The interband contribution is closely linked to the thickness-dependent strain and Mn-$e_{\text{g}}$ level splitting. This effect is attributed to a redistribution of the spin Berry curvature, induced by a structural gradient of octahedral distortions and rotations that breaks inversion symmetry. In contrast, the intraband contribution is attributed to a Rashba-like response in the inversion-symmetry-broken regions. These results indicate that octahedral distortions and rotations in epitaxial LSMO can reshape the Mn-$e_{\text{g}}$ band structure and interband transitions, thereby modifying the intrinsic spin-transport tensor and making the spin polarization components sensitive to structural details. Our work establishes a link between structural distortion and spin current generation in epitaxial LSMO films and provides a basis for designing field-free magnetization switching in single-layer oxide spintronic devices.

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• Magnetization dynamics
• Spin current
• Spin dynamics
• Spin-orbit coupling
• Spin-orbit torque
• Transition metal oxides
• Ferromagnetic resonance