Magnetic Memory from Site Isolated Dy(III) on Silica Materials

Achieving magnetic remanence at single isolated metal sites dispersed at the surface of a solid matrix has been envisioned as a key step toward information storage and processing in the smallest unit of matter. Here, we show that isolated Dy­(III) sites distributed at the surface of silica nanoparticles, prepared with a simple and scalable two-step process, show magnetic remanence and display a hysteresis loop open at liquid ⁴He temperature, in contrast to the molecular precursor which does not display any magnetic memory. This singular behavior is achieved through the controlled grafting of a tailored Dy­(III) siloxide complex on partially dehydroxylated silica nanoparticles followed by thermal annealing. This approach allows control of the density and the structure of isolated, “bare” Dy­(III) sites bound to the silica surface. During the process, all organic fragments are removed, leaving the surface as the sole ligand, promoting magnetic remanence.