Investigations of the Defect Structures and EPR Parameters for the Tetragonal and Cubic Ni2+ Centers in AgX (X=Cl, Br)

Zhi Hong Zhang; Shao Yi Wu; Li Hua Wei; Yue Xia Hu

doi:10.4028/www.scientific.net/DDF.272.117

Paper Titles

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Mathematical Modeling of Interface Movement during Diffusional Bonding of Surfaces
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Growth Kinetics of Boride Layers: A Modified Approach
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Structure and Optical Properties of Magnetron Sputtered SiO_x Layers with Silicon Nanoparticles
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Reaction of Iron with Amorphous Silicon and Crystal Silicon for the Fabrication of Iron Silicides
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Theoretical Determination of Pressure-Volume-Temperature Relationship of Some Alkali Halides
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Investigations of the Defect Structures and EPR Parameters for the Tetragonal and Cubic Ni²⁺ Centers in AgX (X=Cl, Br)
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Concentration Micro-Field for Lamellar Eutectic Growth
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Investigations of the Defect Structures and EPR Parameters for the Tetragonal and Cubic Ni²⁺ Centers in AgX (X=Cl, Br)

Abstract:

The defect structures and the electron paramagnetic resonance (EPR) parameters zero-field splitting and the g factors for the tetragonal and cubic Ni2+ centers in AgX (X=Cl, Br) are theoretically studied from the perturbation formulas of these parameters for a 3d8 ion in tetragonal and cubic octahedra. In these formulas, the ligand s-orbital contributions, which were usually neglected in the previous studies, are taken into account based on the cluster approach. The ligand X− intervening in the Ni2+ and the next nearest neighbour Ag+ vacancy VAg is suggested to suffer a small inward displacement (≈ 0.11 or 0.15Å for AgCl or AgBr, respectively) towards Ni2+ along the [100] (or C4) axis. The calculated EPR parameters based on the above defect structures show reasonable agreement with the experimental data.