Tuning repulsive Casimir forces between an ultra-thin magnetic material and a gold plate

We report on potentially measurable repulsive Casimir forces between ultra-thin magnetic materials and a gold plate. Hendrick Casimir originally predicted an attractive force between perfect conducting plates in vacuum arising from its zero-point energy. T. H. Boyer later showed that replacing one of the plates with an infinitely permeable (magnetic) plate turns the interaction purely repulsive. However, generating repulsion in real-material systems turns out to be nontrivial. Therein, we investigate how the parameters of real material systems, including the permeability, thickness, and temperature, can be tuned to push repulsion into potentially measurable regimes. We also describe the delicate interplay between thickness and permeability, which can potentially allow for levitation of a 2D magnetic material above a metallic plate by counter-balancing gravity.