Ultrafast magnon transistor at room temperature

We study sequential tunneling of magnetic excitations in nonitinerant systems through triangular molecular magnets. It is known that the quantum state of these molecular magnets can be controlled by application of an electric or a magnetic field. Here, we use this fact to control the flow of a pure magnetization current through the molecular magnet by electric or magnetic means. This allows us to design a system that behaves as a magnon transistor. We show how to combine three magnon transistors to form a nand gate, and give several possible realizations of the latter, one of which could function at room temperature using transistors with an 11 ns switching time.