  The large arrays of magnetic dots are the building blocks of magnonic
crystals and the emerging bit patterned media for future recording technology.
In order to fully utilize the functionalities of high density magnetic
nanodots, a method for the selective reversal of a single nanodot in a matrix
of dots is desired. We have proposed a method for magnetization reversal of a
single nanodot with microwave excitation in a matrix of magneto-statically
interacting dots. The method is based on the excitation of collective modes and
the spatial anomaly in the microwave power absorption. We perform numerical
simulations to demonstrate the possibility of switching a single dot from any
initial state of a 3 by 3 matrix of dots, and develop a theoretical model for
the phenomena. We discuss the applicability of the proposed method for
introducing defect modes in magnonic crystals as well as for future magnetic
recording.
