Emergent behavior of LaNiO3 in short-periodic nickelate superlattices

Abstract

Heterostructure engineering provides an efficient way to obtain several emergent phases of LaNiO3, as demonstrated in recent studies. In this work, a new class of short-periodic superlattice, consisting of LaNiO3 and EuNiO3, has been grown by pulsed laser interval deposition to investigate the effect of structural symmetry mismatch on the electronic and magnetic behaviors. Using synchrotron-based soft and hard x-ray resonant scattering experiments, we have found that these heterostructures undergo simultaneous electronic and magnetic transitions. Most importantly, LaNiO3 within these artificial structures exhibits a new antiferromagnetic, charge ordered insulating phase, which may be a potential candidate to achieve high temperature superconductivity.

Defects in complex oxide thin films for electronics and energy applications: challenges and opportunities

“…81,170 The properties of perovskite rare-earth nickelates, RNiO 3 (R = La-Lu), have been attracting enormous attention owing to a rich temperature-composition phase diagram including a metal-to-insulator phase transition coinciding with a nickel charge ordering. 16,171,172 The origin of the metal-to-insulator transition has been widely debated in the literatures. [173][174][175][176] The unoccupied states at the bottom of the conduction band have substantial oxygen character, corresponding to an oxygen ligand hole consistent with a negative charge transfer character for the system.…”

PERSPECTIVE: Emergent phases in rare earth nickelate heterostructures

“…Since RENiO 3 members have a strong tendency to retain their bulk-like symmetry even in thin-film form [80], a strong structural competition is anticipated at the interface between LNO and other members of RENiO 3 . This effect has been indeed observed in ultrathin n uc EuNiO 3 /m uc LaNiO 3 [nENO/mLNO] superlattices (here uc is unit cell in pseudocubic notation, n and m =1, 2) [78,[81][82][83]. The 1ENO/2LNO SL having rhombohedral symmetry remains metallic, whereas the superlattices with n ≥ m have orthorhombic/monoclinic symmetry and exhibit first-order MIT as a function of temperature.…”

“…The competition between interfacial unit cell and bulk-like unit cells were further investigated by growing nENO/nLNO SLs (Fig. 2(a)) [77,78]. The SL with n=8 uc remains metallic, similar to bulk LNO, whereas all short periodic SLs exhibit simultaneous MIT and antiferromagnetic transition (Fig.…”

Non-uniform magnetization profile in ferromagnetic heterostructures leading to topological Hall effect like signatures

“…The tremendous advancement in thin film growth technologies over the last two decades have enabled the research community to grow artificial structures of these complex oxides with unit cell precision [5][6][7][8][9][10][11]. Such heterostructuring [9,[12][13][14][15][16][17][18][19][20][21][22][23][24][25] leads to subtle modifications in spin, charge, orbital, and lattice sectors at the interface, resulting in a variety of emergent magnetic behaviors such as interfacial ferromagnetism, exchange bias, spin spiral magnetic phase, enhanced magnetic ordering temperature, topological Hall effect (THE), etc. THE arises in materials with non-zero scalar spin chirality [𝜒 𝑖,𝑗,𝑘 = 𝑺 𝒊 .…”