Atomic‐Scale Control of Electronic Structure and Ferromagnetic Insulating State in Perovskite Oxide Superlattices by Long‐Range Tuning of BO₆ Octahedra

Abstract

Control of BO 6 octahedral rotations at the heterointerfaces of dissimilar ABO 3 perovskites has emerged as a powerful route for engineering novel physical properties. However, its impact length scale is constrained at 2-6 unit cells close to the interface and the octahedral rotations relax quickly into bulk tilt angles away from interface. Here, a long-range (up to 12 unit cells) suppression of MnO 6 octahedral rotations in La 0.9 Ba 0.1 MnO 3 through the formation of superlattices with SrTiO 3 can be achieved. The suppressed MnO 6 octahedral rotations strongly modify the magnetic and electronic properties of La 0.9 Ba 0.1 MnO 3 and hence create a new ferromagnetic insulating state with enhanced Curie temperature of 235 K. The emergent properties in La 0.9 Ba 0.1 MnO 3 arise from a preferential occupation of the out-of-plane Mn d 3z 2 −r 2 orbital and a reduced Mn e g bandwidth, induced by the suppressed octahedral rotations. The realization of long-range tuning of BO 6 octahedra via superlattices can be applicable to other strongly correlated perovskites for exploring new emergent quantum phenomena.

Manipulating the metal-to-insulator transition and magnetic properties in manganite thin films via epitaxial strain

“…4(b) probe the unoccupied states with partial O 2p feature hybridized with Mn 3d states, La 5d states, and Mn 4sp states. Hence, O K-edge XAS spectra can be qualitatively related to the unoccupied DOS above E f [6,7,30,31]. The overall line-shapes of O K-edge XAS spectra of LBMO thin films are consistent with the reported spectra of La 1−x Sr x MnO 3 [32][33][34].…”

“…Among these TMO materials, the mixed-valence manganite, La 1−x A x MnO 3 (A = Ca, Sr, and Ba), has stimulated considerable interest as it hosts a rich spectrum of physical properties such as the colossal magnetoresistance, half metallicity, the spontaneous charge-spin-orbital ordering, and ferromagnetic insulator behavior [2,3]. Recently, manganite oxide thin films and heterostructures have attracted intensive interest, since many novel electronic and magnetic ground states can be engineered using interface effects [4][5][6][7], defects [1,8], strain engineering [9,10], and different orientations [11].…”

Emergent multiferroism with magnetodielectric coupling in EuTiO3 created by a negative pressure control of strong spin-phonon coupling

“…STEM images in the high-angle annular dark-field (HAADF) mode 21 , 22 , both in cross-section (Fig. 1a ) and plan-view (Fig.…”

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

“…Reproduced with permission. 379 Copyright 2020 Wiley-VCH. SrCoO 2.5 (BM-SCO) with an increase of V O concentration.…”

“…93 On the other hand, recent studies demonstrated that oxygen octahedral coupling (OOC) at the hetero-interfaces can delicately tailor the local BO 6 octahedral rotations at an atomic-scale. [94][95][96][97][98]379 Zhai et al studied the (LaMnO 3 ) n /(SrTiO 3 ) m superlattices and found that the magnitude of ferromagnetic magnetization is strongly correlated with MnO 6 octahedral rotations. 99 A modulation of the emergent interfacial ferromagnetism was realized in (CaRuO 3 ) n /(CaMnO 3 ) m superlattices, comprised of an anti-ferromagnet and a paramagnet, through controlling the rotation patterns.…”