Tailoring the electronic transitions of NdNiO_3 films through (111)_pc oriented interfaces

Bulk NdNiO_3 and thin films grown along the pseudocubic (001)_pc axis display a 1st order metal to insulator transition (MIT) together with a Neel transition at T=200K. Here, we show that for NdNiO3 films deposited on (111)_pc NdGaO_3 the MIT occurs at T=335K and the Neel transition at T=230 K. By comparing transport and magnetic properties of layers grown on substrates with different symmetries and lattice parameters, we demonstrate a particularly large tuning when the epitaxy is realized on (111)_pc surfaces. We attribute this effect to the specific lattice matching conditions imposed along this direction when using orthorhombic substrates.

Electronic Transitions in Strained SmNiO_3 Thin Films

Nickelates are known for their metal to insulator transition (MIT) and an unusual magnetic ordering, occurring at T=T_Neel. Here, we investigate thin films of SmNiO_3 subjected to different levels of epitaxial strain. We find that the original bulk behavior (T_Neel<T_MI) is strongly affected by applying compressive strain to the films. For small compressive strains, a regime where T_Neel=T_MI is achieved, the paramagnetic insulating phase characteristic of the bulk compound is suppressed and the MIT becomes 1st order. Further increasing the in-plane compression of the SmNiO_3 lattice leads to the stabilization of a single metallic paramagnetic phase.