  High perpendicular magnetic anisotropy (PMA), a property needed for nanoscale
spintronic applications, is rare in oxide conductors. We report the observation
of a PMA up to 0.23 MJ/m3 in modestly strained epitaxial NiCo2O4 (NCO) films
which are room-temperature ferrimagnetic conductors. Spin-lattice coupling
manifested as magnetoelastic effect was found as the origin of the PMA. The
in-plane xx-yy states of Co on tetrahedral sites play crucial role in the
magnetic anisotropy and spin-lattice coupling with an energy scale of 1
meV/f.u. The elucidation of the microscopic origin paves a way for engineering
oxide conductors for PMA using metal/oxygen hybridizations.
