Magnetic and Orbital Order in ($R$MnO${}_3$)${}_n$/($A$MnO${}_3$)${}_{2n}$ Superlattices Studied via a Double-Exchange Model with Strain

Abstract

The two-orbital double-exchange model is employed for the study of the magnetic and orbital orders in ($R$MnO${}_3$)${}_n$/($A$MnO${}_3$)${}_{2n}$ ($R$: rare earths; $A$: alkaline earths) superlattices. The A-type antiferromagnetic order is observed in a broad region of parameter space for the case of SrTiO${}_3$ as substrate, in agreement with recent experiments and first-principles calculations using these superlattices. In addition, also a C-type antiferromagnetic state is predicted to be stabilized when using substrates like LaAlO${}_3$ with smaller lattice constants than SrTiO${}_3$, again in agreement with first principles results. The physical mechanism for the stabilization of the A- and C- magnetic transitions is driven by the orbital splitting of the $x^2-y^2$ and $3z^2-r^2$ orbitals. This splitting is induced by the $Q_3$ mode of Jahn-Teller distortions created by the strain induced by the substrates. In addition to the special example of (LaMnO${}_3$)${}_n$/(SrMnO${}_3$)${}_{2n}$, our phase diagrams can be valuable for the case where the superlattices are prepared employing narrow bandwidth manganites. In particular, several non-homogenous magnetic profiles are predicted to occur in narrow bandwidth superlattices, highlighting the importance of carrying out investigations in this mostly unexplored area of research.

11 pages, 10 figures

References in corpus (7)

• Electronic reconstruction at SrMnO3-LaMnO3 superlattice interfaces
• Ferromagnetic tendency at the surface of CE charge-ordered manganites
• Metal-insulator transition in $(LaMn{O}_3{)}_{2n}/(SrMn{O}_3{)}_n$ superlattices
• Magnetically asymmetric interfaces in a (LaMnO${}_3$)/(SrMnO${}_3$) superlattice due to structural asymmetries
• Charge states and magnetic ordering in LaMnO3/SrTiO3 superlattices
• Effects of correlated disorder on the magnetism of double exchange systems
• Optical Properties of (SrMnO3)n/(LaMnO3)2n superlattices: an insulator-to-metal transition observed in the absence of disorder

Cited by in corpus (5)

• Strain Doping: Reversible Single-Axis Control of a Complex Oxide Lattice via Helium Implantation
• Appearance and disappearance of ferromagnetism in ultra-thin LaMnO${}_3$ on SrTiO${}_3$ substrate: a viewpoint from first-principles
• Spin-orbital order in LaMnO${}_3$: $d-p$ model study
• Magnetism and electronic structure of ($001$)- and ($111$)-oriented LaTiO${}_3$ bilayers sandwiched in LaScO${}_3$ barriers
• Orientation-dependent magnetism and orbital structure of strained YTiO${}_3$ films on LaAlO${}_3$ substrates