  The demand for faster magnetization switching speeds and lower energy
consumption has driven the field of spintronics in recent years. The magnetic
tunnel junction is the most developed spintronic memory device in which the
magnetization of the storage layer is switched by spin-transfer-torque or
spin-orbit torque interactions. Whereas these novel spin-torque interactions
exemplify the potential of electron-spin-based devices and memory, the
switching speed is limited to the ns regime by the precessional motion of the
magnetization. All-optical magnetization switching, based on the inverse
Faraday effect, has been shown to be an attractive method for achieving
magnetization switching at ps speeds. Successful magnetization reversal in thin
films has been demonstrated by using circularly polarized light. However, a
method for all-optical switching of on-chip nanomagnets in high density memory
modules has not been described. In this work we propose to use plasmonics, with
CMOS compatible plasmonic materials, to achieve on-chip magnetization reversal
in nanomagnets. Plasmonics allows light to be confined in dimensions much
smaller than the diffraction limit of light. This in turn, yields higher
localized electromagnetic field intensities. In this work, through simulations,
we show that using localized surface plasmon resonances, it is possible to
couple light to nanomagnets and achieve significantly higher opto-magnetic
field values in comparison to free space light excitation.
