Strong photon-magnon coupling using a lithographically defined organic ferrimagnet

SPICE Workshop on Quantum Spinoptics, June 13th - 15th 2023

Greg Fuchs

I’ll discuss recent experiments in which we demonstrate a hybrid quantum system composed of superconducting resonator photons and magnons hosted by the organic ferrimagnet vanadium tetracyanoethylene (V[TCNE]x). Our work is motivated by the challenge of scalably integrating an arbitrarily-shaped, low-damping magnetic system with planar superconducting circuits, thus enabling a new class of quantum magnonic circuit designs. For example, by leveraging the inherent properties of magnons, one can enable nonreciprocal magnon-mediated quantum devices and tunable quantum couplers that use magnon propagation rather than electrical current. We take advantage of the properties of V[TCNE]x, which has ultra-low intrinsic damping, can be grown at low processing temperatures on arbitrary substrates, and can be patterned via electron beam lithography. We demonstrate the scalable, lithographically integrated fabrication of hybrid quantum magnonic devices consisting of a thin-film superconducting resonator coupled to a low-damping, thin-film V[TCNE]x microstructure. Our devices operate in the strong coupling regime, with a cooperativity as high as 1181(44) at T~0.4 K, suitable for scalable quantum circuit integration. This work paves the way for the exploration of high-cooperativity hybrid magnonic quantum devices in which magnonic circuits can be designed and fabricated as easily as electrical wires.