Neodymium‐doping concentration induced face‐shared to corner‐shared transition in Strontium Cobaltite

Haoliang Huang,Liang Xie,Zezhi Chen,Zhengping Fu,Ranran Peng,Yalin Lu,Jianlin Wang

doi:10.1007/s10854-021-05593-3

Abstract

The topotactic connection style of oxygen octahedron/tetrahedron in transition metal oxides (TMOs) is an important feature that modulates their corresponding physical properties. Using a simple chemical doping technique, we obtained Sr1−xNdxCoO3-δ with a crystal structure transition from face-shared octahedron to corner-shared octahedron/tetrahedron. The Rietveld analyses of the X-ray diffraction (XRD) patterns show that the crystal structure changes from rhombohedral to cubic and the connection style transforms from face-shared to corner-shared with the increase neodymium (Nd) content. During this process, the ferromagnetic behavior is greatly improved due to the larger amount of the corner-shared cubic SrCoO3-δ phase. The synchrotron radiation X-ray absorption spectroscopies of the Co L-edge and O K-edge show that Nd-doping mainly affects the electronic structure of oxygen rather than the valence state of Co. Thereby, the Nd changes the connection style of oxygen octahedron/tetrahedron, which then alters the magnetic interactions.

Highlights

Transition metal oxides (TMOs) are a material class with abundant and novel physical properties, such as superconductivity, [1] multiferroicity, [2,3] magnetoresistance, [4] and others
It can be considered that transition metal oxyhydrides with face-shared or edge-shared octahedral that enable much smaller B-O-B angles resulting to versatile magnetic interactions and exhibiting interesting properties
We report the effect of neodymium (Nd) doping on the magnetic properties of strontium cobaltite due to changes in the crystal structure and oxygen coordination environment

Summary

Introduction

Transition metal oxides (TMOs) are a material class with abundant and novel physical properties, such as superconductivity, [1] multiferroicity, [2,3] magnetoresistance, [4] and others. It can be considered that transition metal oxyhydrides with face-shared or edge-shared octahedral that enable much smaller B-O-B angles resulting to versatile magnetic interactions and exhibiting interesting properties. The synchrotron radiation x-ray absorption spectroscopies (XAS) of the Co L-edge and O K-edge provide evidence that the electronic structure of the oxygen vacancies in the SCO system are related to change the connections of CoO6/CoO4 and their magnetic interactions. This work proposes a simple method to realize the transformation from face-shared structure to corner-shared octahedron and to improve the ferromagnetic behavior of strontium cobaltite

Results and discussion

Findings

Conclusions