ORALS

SESSION: SolidStateChemistryTuePM2-R4	Poeppelmeier International Symposium(3rd Intl Symp on Solid State Chemistry for Applications & Sustainable Development)
Tue. 28 Nov. 2023 / Room: Dreams 4
Session Chairs: Alexander Norquist; Session Monitor: TBA

16:25: [SolidStateChemistryTuePM210] OS
STRAINED TUNED STRUCTURES AND FUNCTIONS IN MIXED ANION COMPOUNDS
Hiroshi Kageyama¹ ; ¹Kyoto University, Kyoto, Japan;
Paper Id: 74 [Abstract]

Mixed-anion compounds are attracting attention because of novel functions that are not found in oxides [1]. In this presentation, I show several examples where strain can alter structures and properties of mixed-anion compounds. The first example is anion-vacancy ordered perovskite SrV(O,N)3-x thin film, in which the period and orientation of anion-deficient layers can be altered by biaxial strain from a substrate [2]. In EuVO2H films, substrate strain induces electron transfer from Eu2+ to V3+, resulting in a 4-fold enhancement of the ferromagnetic transition temperature and perpendicular magnetic anisotropy [3]. In addition, in a series of layered oxychalcogenides synthesized at high pressure, the giant tensile strain provided during decompression process from the chalcogen layer can add new functions to the oxide layer [4-5].

References:
[1] H. Kageyama et al., Nat. Commun. 9, 772 (2018). [2] T. Yamamoto et al., Nat. Commun. 11, 5923 (2020). [3] M. Namba et al., submitted. [4] Y. Matsumoto et al., Angew. Chem. Int. Ed. 57, 756 (2019). [5] Y. Yang et al., Inorg. Chem. 61, 7026 (2022).

SESSION: SolidStateChemistryWedPM1-R4	Poeppelmeier International Symposium(3rd Intl Symp on Solid State Chemistry for Applications & Sustainable Development)
Wed. 29 Nov. 2023 / Room: Dreams 4
Session Chairs: Paul Salvador; Session Monitor: TBA

15:20: [SolidStateChemistryWedPM108] OS
STRAIN ENGINEERING IN MIXED-ANION PEROVSKITES
Hiroshi Kageyama¹ ; ¹Kyoto University, Kyoto, Japan;
Paper Id: 190 [Abstract]

Perovskite oxides ABO3 continue to be a major subject in materials science because of its chemical and structural diversity1. Of particular interest is the interplay between A and B cations with finite d/f electrons, which, for example, causes inter-site charge transfer (ICT), leading to novel phenomane such as negative thermal expansion and metal-to-insulator transitions. The ICT properties are controlled by cationic substitution, but the mechanism is complicated by three-dimensional (3D) structures. Mixed-anion compounds began to draw attention as game-changing inorganic materials. Since, compared with conventional inorganic compounds such as oxides, mixed-anion compounds may exhibit unique coordination and resultant extended structures, from which fundamentally different chemical and physical property may emerge. In my talk, a new oxyhydride EuVO2H, prepared via anion-exchange reactions of EuVO3perovskite oxide, will be presented [1]. EuVO2H with alternating layers of EuH and VO2 exhibit ICT between the heteroanion layers. While bulk EuVO2H is a ferromagnetic insulator with TC = 10 K, application of external pressure or biaxial strain from a substrate to a EuVO2H film causes ICT to occur from the EuIIH layer to the VIIIO2 layer. The strained film exhibits a 4-fold increase in TC and, despite the absence of orbital angular momentum, Eu2+ exhibits giant magnetic anisotropy with its easy axis perpendicular to the film, which is favorable for devices such as high-density memory. The present results provide new possibilities for the acquisition of novel functions by alternating layered structures of heteroanions. If time allows, other examples of strain engineering of perovskite structures and properties including SrV(O,N)3-x [2]will be presented.

References:
[1] Nambe et al., submitted. [2] Yamamoto et al., Nat. Commun 11, 5923 (2020)