  Devices for performing computation and logic operations with low-energy
consumption are of key importance for environmentally friendly data-processing
and information technology. Here, we present a design for magnetic elements
that use excess heat to perform logic operations. The basic information channel
is coupled non-conductive magnetic stripes with a normal metal spacer. The
thermal information signal is embodied in magnetic excitations and it can be
transported, locally enhanced, and controllably steered by virtue of charge
current pulses in the spacer. Functionality of essential thermal logic gates is
demonstrated by material-specific simulations. The operation principle takes
advantage of the special material architecture with a balanced gain/loss
mechanism for magnetic excitation which renders the circuit parity-time
symmetric with exceptional points tunable by the current strength in the
spacer. Heat flow at these points can be enhanced, be non-reciprocal, or may
oscillate between the information channels enabling so controlled thermal diode
and thermal gate operations. The findings point to a new route for exploiting
heat for useful work on the nanoscale.
