Electronic Structure of A- and B-Site Doped Lanthanum Manganites: A Combined X-ray Spectroscopic Study

Magnetoresistance (MR) properties of magnetic materials

In this review, the classification of magnetic materials exhibiting magnetoresistive properties is the focus of discussion because each material possesses different magnetic and electrical properties that influence the resulting magnetoresistance (MR) values. These properties depend on the structure and mechanism of the material. In this overview, the classification of magnetic materials with different structures is examined in several material groups, including the following: (1) perovskite structure (ABO3), (2) alloy, (3) spinel structure, and (4) Kagome magnet. This review summarizes the results of each material's properties based on experimental findings, and serves as a reference for studying the characteristics of each material.

Depth profiling charge accumulation from a ferroelectric into a doped Mott insulator

The electric field control of functional properties is a crucial goal in oxide-based electronics. Nonvolatile switching between different resistivity or magnetic states in an oxide channel can be achieved through charge accumulation or depletion from an adjacent ferroelectric. However, the way in which charge distributes near the interface between the ferroelectric and the oxide remains poorly known, which limits our understanding of such switching effects. Here, we use a first-of-a-kind combination of scanning transmission electron microscopy with electron energy loss spectroscopy, near-total-reflection hard X-ray photoemission spectroscopy, and ab initio theory to address this issue. We achieve a direct, quantitative, atomic-scale characterization of the polarization-induced charge density changes at the interface between the ferroelectric BiFeO3 and the doped Mott insulator Ca(1-x)Ce(x)MnO3, thus providing insight on how interface-engineering can enhance these switching effects.

Direct Investigation of Orbital Ordering in a Colossal Magnetoresistance Manganite by Means of X-ray Linear Dichroism at the Mn L Edge

We have investigated for the first time the orbital ordering in a three-dimensional colossal magnetoresistance manganite, namely La(7/8)Sr(1/8)MnO3, by applying soft X-ray linear dichroism (XLD) to the Mn L edge. We found that the cooperative Jahn-Teller distorted orthorhombic phase, which is present at a temperature of 240 K, is probably accompanied by a predominantly cross type (x2 - z2)/(y2 - z2) orbital ordering. This result is discussed in the light of different exchange interaction models.