Room-temperature magnetism in ${\text{LaVO}}_3/{\text{SrVO}}_3$ superlattices by geometrically confined doping

Based on the Hubbard model of strongly correlated systems, a reduction in the bandwidth of the electrons can yield a substantial change in the properties of the material. One method to modify the bandwidth is geometrically confined doping, i.e., the introduction of a (thin) dopant layer in a material. In this Rapid Communication, the magnetic properties of ${\text{LaVO}}_3/{\text{SrVO}}_3$ superlattices, in which the geometrically confined doping is produced by a one monolayer thick ${\text{SrVO}}_3$ film, are presented. In contrast to the solid solution ${\text{La}}_{1-x}{\text{Sr}}_x{\text{VO}}_3$, such superlattices have a finite magnetization up to room temperature. Furthermore, the total magnetization of the superlattice depends on the thickness of the ${\text{LaVO}}_3$ layer, indicating an indirect coupling of the magnetization that emerges at adjacent dopant layers. Our results show that geometrically confined doping, like it can be achieved in superlattices, reveals a way to induce otherwise inaccessible phases possibly even with a large temperature scale.

Figure 1

(Color online) (a) Sketch of the superlattice in the ac plane. (b) $\theta \text{−}2\theta$ scan of a high pressure $m=6$ sample. A superlattice satellite peak is indicated by its order number. The reflection indicated by a star is from the sample holder. Inset: zoom on the superlattice Bragg peak of a $m=5$ sample.

Figure 2

(Color online) Magnetization vs magnetic field for a high pressure $m=6$ superlattice (circles) at 10 and 300 K and the solid solution single layer (squares) at 10 K. Inset: normalized magnetization of the same supperlattice vs temperature in an applied field of 500 Oe.

Figure 3

(Color online) Magnetization vs magnetic field for the high pressure series with $m$ ranging from 2 to 6 at 10 K.

Figure 4

(Color online) Saturation magnetization of the superlattices of the high pressure series (solid squares) and the low pressure series (open circles) vs $m$ at 10 K. The sketches in the figure show a possible magnetic structure of the superlattice.