Electronic structure of the (Nd1−xDyx)2Fe14B (0 ≤ x ≤ 1) system studied by X-ray photoelectron spectroscopy

Jing Wang,Bin Yang,Lan-Ting Zhang,Shin-Ichi Hirano,Le Liang,Li-Min Sun

doi:10.1063/1.4931920

Abstract

Systematic characterization of electronic structures in the (Nd1−xDyx)2Fe14B system, especially the 4f behavior, provides an insight to the physical nature of the evolution of magnetic properties. A series of X-ray photoelectron spectroscopy (XPS) core-level and valence-band spectra were used to study the electronic structures. It was found that substitution of Dy for Nd in Nd2Fe14B results in a nonlinear variation in the evolution of electronic structures. Only the finite coupling between the Nd 4f states and the Fe 3d states is found at both the Nd-rich regime and the Dy-rich regime. When the Dy concentration and the Nd concentration approach to be equal, a strong coupling between the Nd 4f states and the Fe 3d states is found, which results in a bonding state between them. Additionally, the 4f components in the (Nd1−xDyx)2Fe14B system are ascribed to three parts: 1) the individual contribution of the Dy 4f states, which emerges just after the Dy-substitution; 2) the contribution of the coupling between the Nd 4f states and the Dy 4f states, which arises only when 0.4 ≤ x ≤ 0.6; 3) the associated contributions of the Nd 4f states and the Dy 4f states, where the contribution of the Nd 4f states and that of the Dy 4f states are prominent in the Nd-rich regime and Dy-rich regime, respectively.

Highlights

The relationship between electronic structure and magnetic nature is one of the attractive subjects in strongly correlated electron systems, such as rare-earth (R) transition-metal (TM) compounds.[1,2,3,4,5] R2Fe14B-type compounds are a group of technologically important magnetic compounds, which have tetragonal crystalline structures.[6]
When the Dy concentration and the Nd concentration approach to be equal, a strong coupling between the Nd 4 f states and the Fe 3d states is found, which results in a bonding state between them
We have studied the electronic structures of the Nd, Dy, Fe and B in the (Nd1−xDyx)2Fe14B system as a function of the Dy concentration

Summary

Introduction

The relationship between electronic structure and magnetic nature is one of the attractive subjects in strongly correlated electron systems, such as rare-earth (R) transition-metal (TM) compounds.[1,2,3,4,5] R2Fe14B-type compounds are a group of technologically important magnetic compounds, which have tetragonal crystalline structures.[6] Among them, Nd2Fe14B shows a large saturation magnetization Ms, while Dy2Fe14B bears a substantial magnetic anisotropy field HA. The substitution of Dy for Nd in Nd2Fe14B results in a linear increase in HA and a corresponding linear decrease in Ms.[7,8,9,10] Since the magnetic property is sensitive to the electronic structure, a preliminary speculation is proposed that the electronic structure in the (Nd1−xDyx)2Fe14B system would be in a linear variation. The purpose of our work is to confirm this speculation

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Results

Conclusion