Scientists at the University of Manchester have discovered that placing magnetic films on atomically thin molybdenum disulfide (MoS₂) fundamentally changes how they lose energy, a finding that could bring 2D‑material spintronics a step closer to real devices. The team found that growing a widely used magnetic alloy, permalloy, on ultra‑thin MoS₂ alters the film's internal crystal structure, changing how and where energy is lost as magnetic spins move. By separating energy losses that occur at the surface of the film from those arising within its internal structure, the researchers provide new design insights for devices that use two‑dimensional (2D) materials to control magnetism more efficiently.