三元軟鐵磁性塊材金屬玻璃Fe78-xYxB22 (x= 4-9) 磁性與電子結構

Correlation between magnetic properties and the electronic structures of soft magnetic ternary Fe78-xYxB22 (x= 4-9) bulk metallic glasses

劉明聰(Ming-Tsung Liu)

指導教授 ： 彭維鋒

淡江大學/理學院/物理學系碩士班/碩士(2010年)

https://doi.org/10.6846/TKU.2010.01058

摘要

Fe和Y K-egde的延伸X光吸收精細結構(Extended x-ray absorption fine structure，EXAFS)，Fe (Y) L3,2-edge (L3-edge) X光吸收近邊緣結構(X-ray absorption near-edge structure，XANES)和價帶光電子發射能譜學(Valence-band photoemission spectroscopy，VB-PES)測量研究 Fe78-xYxB22 (x= 4-9)三元軟鐵磁性塊材金屬玻璃(bulk metallic glasses，BMGs)的磁性與電子結構。在Fe L3,2-edge光譜中，利用Branching ratio所得的數值與磁性量測所得的單位鐵原子之有效波爾磁子數，其結果均顯示當隨著Y含量遞增有著相同的減弱趨勢，卽磁矩隨Y的濃度增加而減少。在XANES和VB-PES研究的結果中，發現當以Y摻入樣品中引起Fe磁矩的減弱，可理解因為在Ef附近可能由於去局域化/巡迴電子密度的減少。推論其鐵磁性耦合強度的減弱，顯示Fe 3d離子之局域自旋組態影響鐵基非晶塊材合金之總磁矩的關係。

關鍵字

X光吸收近邊緣結構 ； 延伸X光吸收精細結構 ； 價帶光電子發射能譜學

並列摘要

Fe and Y K-edge extended x-ray absorption fine structure (EXAFS), Fe (Y) L3,2-edge (L3-edge) x-ray absorption near-edge structure (XANES) and valence-band photoemission spectroscopy (VB-PES) measurements have been carried out to study soft magnetic ternary Fe78-xYxB22 bulk metallic glasses (BMGs). The combined XANES and VB-PES results do not show broadening of the Fe 3d band to support previous interpretation of the reduction of the magnetic moment in BMGs by Y-induced decrease of exchange splitting of Fe 3d orbitals. Instead, the density of delocalized/itinerant Fe 3d states in the vicinity of the Fermi level is found to be reduced by Y substitution, which reduces the strength of itinerant-states mediated ferromagnetic coupling between local spins on the Fe ions and the total magnetic moment of the Fe-based BMGs.

並列關鍵字

XANES ； EXAFS ； VB-PES

參考文獻

1.N. DeCristofaro, MRS Bull. 23, 50 (1998).

2.B. Shen, C. Chang, Z. Zhang, and A. Inoue, J. Appl. Phys. 102, 023515 (2007).

3.K. F. Yao and C. Q. Zhang, Appl. Phys. Lett. 90, 061901 (2007).

6.A. García-Arribas, M. L. Fdez-Gubieda, I. Orúe, J. M. Barandiarán, J. Herreros, and F. Plazaola,Phys. Rev. B 52, 12805 (1995).

8.M. L. Fdez-Gubieda, A. García-Arribas, J. M. Barandiarán, R. López Antón, I. Orue, P. Gorria, S.Pizzini, and A. Fontaine, Phys. Rev. B 62, 5746 (2000).