Resolving diverse oxygen transport pathways across Sr-doped lanthanum ferrite and metal-perovskite heterostructures
Sandra D. Taylor, Kayla H. Yano, Michel Sassi, Bethany E. Matthews, Sten V. Lambeets, Sydney Neumann, Daniel K. Schreiber, Le Wang, Yingge Du, Steven R. Spurgeon
Perovskite structured transition metal oxides are important technological materials for catalysis and solid oxide fuel cell applications. Their functionality often depends on oxygen diffusivity and mobility through complex oxide heterostructures, which can be significantly impacted by structural and chemical modifications, such as doping. Further, when utilized within electrochemical cells, interfacial reactions with other components (e.g. Ni- and Cr-based alloy electrodes and interconnects) can influence the perovskite's reactivity and ion transport, leading to complex dependencies that are difficult to control in real-world environments. Here we use isotopic tracers and atom probe tomography to directly visualize oxygen diffusion and transport pathways across perovskite and metal-perovskite heterostructures, i.e. (Ni-Cr coated) Sr-doped lanthanum ferrite (LSFO). Annealing in 18O2(g) results in elemental and isotopic redistributions through oxygen exchange (OE) in the LSFO while Ni-Cr undergoes oxidation via multiple mechanisms and transport pathways. Complementary density functional theory (DFT) calculations at experimental conditions provide rationale for OE reaction mechanisms and reveal a complex interplay of different thermodynamic and kinetic drivers. Our results shed light on the fundamental coupling of defects and oxygen transport in an important class of catalytic materials.
Magnetoelectric Coupling in Nickel-Cobalt Ferrite and Lanthanum Ferrite Heterostructure Composites: Experimental Evidence and Simulation-Driven Insights
Designing heterostructures to control oxygen stoichiometry in helimagnetic perovskite strontium ferrite
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory（斯坦福材料能源科学研究所，SLAC国家加速器实验室）；Department of Applied Physics, Stanford University（斯坦福大学应用物理系）；Department of Materials Science and Engineering, Northwestern University（西北大学材料科学与工程系）；Catalan Institute of Nanoscience and Nanotechnology (ICN2)（加泰罗尼亚纳米科学与纳米技术研究所（ICN2））；School of Applied and Engineering Physics, Cornell University（康奈尔大学应用与工程物理学院）；Center for Nanophase Materials Sciences, Oak Ridge National Laboratory（橡树岭国家实验室纳米材料科学中心）；Department of Material Science Engineering, Pusan National University（釜山大学材料科学与工程系）；Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory（SLAC国家加速器实验室斯坦福同步辐射光源）
Metal-insulator transition and electroresistance in lanthanum/calcium manganites La_<1-x>Ca_<x>MnO_<3> (x = 0-0.5) from voltage-current-temperature surfaces
Unveiling the outstanding oxygen mass transport properties of Mn-rich perovskites in grain boundary-dominated La0.8Sr0.2(Mn1-xCox)0.85O3-d nanostructures
Magnetic phase diagram of rare-earth orthorhombic perovskite oxides
自旋重取向和磁化反转是稀土斜方镁铁榴石（$RM$ O $_{3}$ 's）的两个重要特征，引起了人们的广泛关注，但其确切的微观起源一直没有得到研究者的证实。在这里，使用密度泛函理论和经典的原子自旋动力学，我们建立了一个通用的海森堡磁性模型，允许探索整个相图的铬铁矿和铁氧体化合物，并仔细检查负责自旋重新取向和磁化反转的微观机制。我们表明，磁化反转转变的发生取决于稀土和过渡金属原子之间的相互作用的相对强度和符号：超交换和Dzyaloshinsky-Moriya。我们还得出结论，所谓的$Γ_4$和$Γ_2$阶段之间存在一个平滑的自旋重取向过渡，通过共存区域，以及它发生的温度范围，取决于微妙的平衡金属-金属（超交换和Dzyaloshinsky-Moriya）和金属-稀土（Dzyaloshinsky-Moriya）耦合。特别是，我们表明，中间共存区的发生，因为自旋子晶格以不同的速率旋转。
Confinement of electron holes via the peroxo group formation in the negative charge-transfer materials on the example of SrFeO3: plane-wave density functional theory predictions
