ABSTRACT
Motivated by recent measurement of the magnetism and conductance of the oxygen-assisted Pt nanojunctions, we performed first principle calculations of the magnetic order and electronic transport by explicitly including fully relativistic effects. Our results show that the spin alignment is a cycloidal spiral feature attributed to the Dzyaloshinskii-Moriya interaction, which indicates that the observed magnetism in experiments is of noncollinear nature. The oxygen concentration is the responsible for the switching of the rotational sense of the spiral magnetic order found in oxygen-assisted Pt nanojunctions. Furthermore, the magnetic moments and magnetoresistances vary with oxygen concentration in the chain, which can be used to tune the magnetism and magnetotransport. The oxygen-assisted Pt nanojunctions offer a possibility for spintronic applications in magnetic memory and quantum devices.