Alexander Boris

We performed the first low-energy muon spin rotation (LE-muSR) measurements on superlattices (SLs) consisting of alternating atomic-scale layers of the correlated metal LaNiO3 and the band insulator LaAlO3. Combining the new LE-muSR results with our previous studies of the charge dynamics, we found that LaNiO3/LaAlO3 SLs exhibit a temperature-driven transition from an itinerant paramagnetic to a localized magnetically ordered state for LaNiO3 thicknesses of 2 unit cells (u.c.). To the contrary, SLs with thicker LaNiO3 remained metallic and paramagnetic down to the lowest temperatures. Curiously, for the 2 u.c. LaNiO3 - based SLs the magnetic transition temperature TM ˜ 40 K is much lower than the metal-insulator transition Tt ˜ 150 K. We propose to further explore the nature of the magnetically ordered state by means of low-energy muon-spin-rotation measurements on nickelate-based ultrathin layers with different rare earth ions R (R =La, Nd, Dy) alternated by insulating material layers of variable thicknesses.