  A new proposal is given to design a spin half-adder in a nano-junction. It is
well known that at finite voltage a net circulating current (known as circular
current) appears within a mesoscopic ring under asymmetric ring-to-electrode
interface configuration. This circular current induces a finite magnetic field
at the center of the ring. We utilize this phenomenon to construct a spin half
adder. The circular current induced magnetic field is used to regulate the
alignments of local free spins, by their orientations we specify the output
states of the `sum' and `carry'. All the outputs are spin based, therefore the
results get atomically stored in the system. We also illustrate the
experimental possibilities of our proposed model.
