Carrier-tunable RKKY magnetism in a crystalline magnet
In itinerant magnets governed by the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, the exchange coupling depends on both the moment-moment distance $r$ and the Fermi wavevector $k_{\mathrm{F}}$, yet in bulk synthesis the two are tightly coupled: a change in composition typically alters both. Here, we use a thin-fil...