剛玉材料 Cr₁.₀₅V₀.₈₅O₃ 磁性與自旋-聲子交互作用之研究;Magnetism and Spin–Phonon Coupling in Cr₁.₀₅V₀.₈₅O₃ with Corundum Structure

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/97821

Title:	剛玉材料 Cr₁.₀₅V₀.₈₅O₃ 磁性與自旋-聲子交互作用之研究;Magnetism and Spin–Phonon Coupling in Cr₁.₀₅V₀.₈₅O₃ with Corundum Structure
Authors:	程浚邑;Cheng, Chun-Yi
Contributors:	物理學系
Keywords:	CrVO3;剛玉材料;反鐵磁有序結構;自旋-聲子交互作用;CrVO3;corundum material;Antiferromagnetic ordered structure;Spin-phonon interaction
Date:	2025-07-30
Issue Date:	2025-10-17 11:57:06 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究旨在研究剛玉類氧化物材料 Cr₁.₀₅V₀.₈₅O₃ 材料的磁性與內部自旋聲子交互作用之現象。透過X光粉末繞射、中子繞射、穿透式電子顯微鏡、X光吸收光譜、物理特性量測系統、拉曼光譜技術，詳細分析了該材料之晶體結構、磁性行為與自旋聲子交互作用。研究結果顯示，Cr₁.₀₅V₀.₈₅O₃ 由3.5K到300K均為Hexagonal R-3c 結構，該區間內並未發生明顯的結構相變。同時中子繞射實驗顯示材料至3.5 K至300 K 呈現沿c軸的反鐵磁性，磁矩強度由1.23 μ_B/atom隨溫度上升而下降，到200 K 時的磁相變溫度材料內自旋排列發生轉變，磁矩大小降至0.50 μ_B/atom，該下降幅度經由 Bloch T3/2 law 擬合，以 10 K 至 85 K區間理論最大磁矩 M_0≈1.24(3) μ_B/atom 、T_C≈356.89 K， 90 K 至 200 K區間其理論最大磁矩 M_0≈1.33(5) μ_B/atom 、T_C≈285.4 K。在4 K時呈現明顯的磁滯現象，50 K過後磁滯現象則隨溫度上升而更加不明顯，矯頑力與殘磁也都接近於零。透過變溫拉曼、等溫變磁拉曼、變功率拉曼等實驗，搭配變溫中子繞射、磁化率實驗、磁滯曲線實驗可以計算晶格間自旋聲子耦合常數、單自旋之自旋聲子耦合常數，並觀察到在自旋有序變化間Raman Shift的變化。這些特徵都表明了 Cr₁.₀₅V₀.₈₅O₃ 材料在磁相變溫度前後自旋聲子交互作用與磁性間的變化，顯示了該材料在磁性儲能、自旋聲子學、磁電效應等領域皆具有相當的潛力。 ;This study investigates the magnetic properties and spin–phonon interactions in the corundum-type oxide Cr₁.₀₅V₀.₈₅O₃. Using X-ray powder diffraction, neutron diffraction, TEM, X-ray absorption spectroscopy, PPMS, and Raman spectroscopy, we comprehensively analyzed its crystal structure, magnetic behavior, and spin–phonon coupling. Results show that Cr₁.₀₅V₀.₈₅O₃ retains a hexagonal R-3c structure from 3.5 K to 300 K without structural phase transitions. Neutron diffraction reveals c-axis antiferromagnetic ordering throughout this range. The magnetic moment decreases from 1.23 μB/atom at low temperature to 0.53 μB/atom near 200 K, indicating a transition from long-range to short-range magnetic order. This trend follows the Bloch T³⁄² law with an exponent of 2 and an estimated TC≈260TC. Magnetic hysteresis is evident at 4 K but vanishes above 50 K, with coercivity and remanence approaching zero. Temperature-dependent, field-dependent, and power-dependent Raman measurements—alongside neutron and magnetization data—enabled calculation of both inter-spin and single-spin spin–phonon coupling constants. A distinct Raman shift change is observed between long-range and short-range ordered states. These findings demonstrate the evolving spin–phonon interaction and magnetism near the magnetic transition temperature, highlighting the potential of Cr₁.₀₅V₀.₈₅O₃ in magnetic energy storage, spin-phononics, and magnetoelectric applications.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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