An anisotropic cosmological model with spin-(1/2) particles

In the context of the ECSK theory of gravitation it is obtained the solutions of the Einstein-Dirac equations in a Bianchi I-type universe with plane symmetry. The plane symmetry is imposed by spin, which, according to the field equations, has only one non-zero space component. The metric tensor is singular: spin dominates in a neighbourhood of the singularities, delaying the isotropization, whereas mass-energy rules the damping of the anisotropy at late times (t → ± ∞). At late times, the metric tensor becomes the FRW one of the spatially flat universe, when the source is a perfect fluid with zero pressure