Cooperative liquid-like paramagnetic state in nanoengineered honeycomb lattice

Geometrically frustrated honeycomb structured artificial magnetic lattice has emerged as a testbed to explore the competing physics of energy vs. entropy in a thermally tuned magnetic phase transition. A magnetic honeycomb lattice with competing exchange interactions between Ising moments is theoretically predicted to exhibit disordered magnetic state with macroscopic degeneracy. We demonstrate the realization of a liquid-like magnetic state, comprised of low integer and energetically forbidden high integer magnetic charges, in nanostructured magnetic honeycomb lattice of ultra-small, sub-12 nm, connecting elements. Magnetic charges, related to magnetic moment and interacting via magnetic Coulomb's interaction, act as quantum mechanical entities. Detailed polarized neutron reflectometry measurements on magnetic honeycomb reveal a robust degenerate ground state at low temperature, which remains minimally affected by magnetic field application. Our finding provides a new vista to investigate quantum mechanical phenomena from the perspective of dynamic magnetic charges, instead of magnetic moments, in a classical system.