  The field of magnonics offers a new type of low-power information processing,
in which magnons, the quanta of spin waves, carry and process data instead of
electrons. Many magnonic devices were demonstrated recently, but the
development of each of them requires specialized investigations and, usually,
one device design is suitable for one function only. Here, we introduce the
method of inverse-design magnonics, in which any functionality can be specified
first, and a feedback-based computational algorithm is used to obtain the
device design. Our proof-of-concept prototype is based on a rectangular
ferromagnetic area which can be patterned using square shaped voids. To
demonstrate the universality of this approach, we explore linear, nonlinear and
nonreciprocal magnonic functionalities and use the same algorithm to create a
magnonic (de-)multiplexer, a nonlinear switch and a circulator. Thus,
inverse-design magnonics can be used to develop highly efficient rf
applications as well as Boolean and neuromorphic computing building blocks.
