  We investigated theoretically electronic and magnetic properties of the
perovskite material SrCoO$_{3-\delta}$ with $\delta\leq 0.15$ using a
projector-augmented plane-wave method and a Green's function method. This
material is known from various experiments to be ferromagnetic with a Curie
temperature of 260$\,$K to 305$\,$K and a magnetic moment of
1.5${\,\mu_\text{B}}$ to 3.0${\,\mu_\text{B}}$. Applying the magnetic force
theorem as it is formulated within Green's function method, we calculated for
SrCoO$_{3-\delta}$ the magnetic exchange parameters and estimated the Curie
temperature. Including correlation effects by an effective $U$ parameter within
the GGA$+U$ approach and verifying this by hybrid functional calculations, we
obtained the Curie temperatures in dependence of the oxygen deficiency close to
the experimental values.

Materials Science