Magnonic combinatorial memory for high-density data storage

In this work, we describe Magnonic Combinatorial Memory (MCM), where the bits of information are stored in the signal propagation paths in the network. MCM is an active ring circuit consisting of electric and magnonic parts. The electric part includes a broadband amplifier, phase shifters, and frequency filters. The magnonic part is a mesh of frequency-dependent elements. Signal propagation path(s) in the mesh depend on the amplitude/phase matching between the electric and magnetic parts. The operation of the MCM is described based on the network model, where information is encoded in the S-parameters of the network elements as well as in the element arrangement in the network. We present experimental data for MCM with a four-terminal magnonic element. The element consists of a single-crystal yttrium iron garnet Y3Fe2(FeO4)3 film and magnets on top of the film. The results demonstrate a robust operation of MCM with an On/Off ratio for path detection exceeding 50 dB at room temperature. The number of possible arrangements scales factorially with the number of magnets, which allows us to drastically increase the data storage density. Physical limits of MCM are also discussed.