  We address spin dependent transport through an array of diamonds in the
presence of Rashba spin-orbit (SO) interaction where each diamond plaquette is
penetrated by an Aharonov-Bohm (AB) flux $\phi$. The diamond chain is attached
symmetrically to two semi-infinite one-dimensional non-magnetic metallic leads.
We adopt a single particle tight-binding Hamiltonian to describe the system and
study spin transport using Green's function formalism. After presenting an
analytical method for the energy dispersion relation of an infinite diamond
chain in the presence of Rashba SO interaction, we study numerically the
conductance-energy characteristics together with the density of states of a
finite sized diamond network. At the typical flux $\phi=\phi_0/2$, a
delocalizing effect is observed in the presence of Rashba SO interaction, and,
depending on the specific choices of SO interaction strength and AB flux the
quantum network can be used as a spin filter. Our analysis may be inspiring in
designing spintronic devices.
