EFFECTS OF HEAT TREATMENT ON SPIN HAMILTONIAN PARAMETERS OF Cr3+ IONS IN NATURAL PINK SAPPHIRE

The purpose of this research work is to investigate the effects of heat treatment on spin Hamiltonian parameters of Cr 3+ ions in natural pink sapphire sample. The pink sapphire were heated at different temperatures of 1200, 1300, 1400, 1500 and 1600°C in oxygen atmosphere for 12 h, respectively. Electron Spin Resonance (ESR) spectra of pink sapphire samples before and after heat treatment were recorded in X-band frequency by mounting the crystal sample with the c-axis perpendicular to the applied magnetic field direction. The spectra were recorded in the range of 0-180 degrees for every 15 degrees of rotation angle (φ). It was found that, five strong ESR absorption peaks at the magnetic fields of 97, 163, 312, 519 and 724 mT were obtained. The magnetic fields of 163 and 519 mT corresponding to Cr 3+ ions replacing the Al 3+ ions site of corundum structure (α- Al 2 O 3), and those of 97, 312, and 724 mT were assigned to Fe 3+ ions. Some conspicuous peaks of Cr 3+ ion at various rotation angles were used to calculate the spin Hamiltonian parameters by least-squares fit method with the help of a computer program. The optimum spin Hamiltonian parameters of Cr 3+ ions were then used to simulate the energy levels diagram of Cr 3+ ions in sample before and after heat treatment.

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ESR STUDY OF SPIN-HAMILTONIAN PARAMETERS AND CRYSTAL FIELD ENERGY LEVELS FOR THE LOW C3 SYMMETRY Fe3+ CENTER IN GREEN SAPPHIRE CRYSTALS AND POWDER

Modern Physics Letters B ◽

10.1142/s0217984907012505 ◽

2007 ◽

Vol 21 (04) ◽

pp. 225-236 ◽

Cited By ~ 2

Author(s):

P. LIMSUWAN ◽

N. UDOMKAN ◽

P. WINOTAI

Keyword(s):

Rotation Angle ◽

Energy Levels ◽

Heat Treating ◽

Esr Spectra ◽

Field Energy ◽

Hamiltonian Matrix ◽

Magnetic Field Direction ◽

Spin Hamiltonian ◽

Corundum Structure ◽

Hamiltonian Parameters

In this report, Fe 3+ impurity ions present in green sapphire ( Al 2 O 3) were studied experimentally, by heating a light green sapphire in flowing oxygen atmosphere for 12 h from 1200, 1300, 1400, 1500 and 1600°C, respectively. Electron spin resonance (ESR) spectra in X-band (~9.45 GHz ) were recorded by mounting the crystal with the c-axis perpendicular (θ = 90°) to the magnetic field direction. The spectra were recorded and simulated by a numerical diagonalization of spin Hamiltonian matrix in the range from 0 to 180 degrees for every 15 degrees of rotation angle (φ). In our case, only the last two sets of peaks strongly depend on the rotation angle (φ), and each exhibits C 3 symmetry due to two magnetically inequivalent Fe 3+ sites in the corundum structure. For polycrystalline ESR spectra, seven main Fe 3+ ESR absorption peaks occur at the resonance magnetic fields of 100.20, 310.24, 486.80, 525.00, 550.60, 761.00 and 777.00 mT respectively. Specifically, ESR signals show that the number of paramagnetic Fe 3+ ions increase roughly linearly with the heat treating temperature, having the [Formula: see text] ratio ~1.41 at 1600°C.

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EPR Spectroscopy Elucidates the Electronic Structure of [FeV(O)(TAML)] Complexes

Inorganic Chemistry Frontiers ◽

10.1039/d1qi00522g ◽

2021 ◽

Author(s):

Yujeong Kim ◽

Jin Kim ◽

Linh. K. Nguyen ◽

Yong-Min Lee ◽

Wonwoo Nam ◽

...

Keyword(s):

Electronic Structure ◽

Epr Spectroscopy ◽

Macrocyclic Ligands ◽

Spin Hamiltonian ◽

Pulse Epr ◽

Hamiltonian Parameters

Multifrequency, multitechnique pulse EPR spectroscopy was employed to unravel the spin Hamiltonian parameters of 17O in the [FeV=O] moiety with two different tetraamido macrocyclic ligands (TAMLs), [FeV(O)(TAML-1)]– (1, H4(TAML-1) =...

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