  The magnetic and spin transport properties of a carbon chain between two
armchair graphene nanoribbon (AGNR) electrodes were studied using tight-binding
Hamiltonian, mean-field Hubbard model and Landauer-Butikker formalism. The
results showed that only odd-numbered carbon chains show intrinsic magnetic
moments in chain-graphene junctions. It was also found that the electronic,
magnetic and spin transport properties of carbon chain-graphene junctions
strongly depend on the position and the length of the carbon chains between
AGNR electrodes. Interestingly, we found a fully spin-polarized transmission
near the Fermi energy in all odd-numbered carbon chain-graphene junctions,
regardless of their lengths and without any magnetic field and magnetic
electrodes.
