High frequency characterization of the thin film ferrites BaM and YIG

New microwave electronic technology challenges require the integration of many passive components onto chips. Among them, isolators and circulators are non-reciprocal passive devices that contain magnetic materials. It is therefore important to know the magnetic properties of suitable materials. The permeability tensor is the most important parameter to define, because it governs the interaction between the electromagnetic wave and the material, and is thus the origin of all magnetic phenomenons. Our work consists of performing the characterization of thin films of BaM and YIG over a frequency range of 0.4 GHz to 65 GHz. The work shows the presence of a gyroresonance phenomenon and locates the resonance frequencies. The technique is based on S parameter measurements on the magnetic materials performed with a network analyser and a probe tester. Polder's model is used to calculate the different elements of the permeability tensor, which consider the ferrite in its saturated state

Prediction study of structural, electronic and optical properties of 4C16H10Br2O2 Bis (m-bromobenzoyl) methane crystals

By first-principles calculations with density functional theory and a pseudopotential approach, the structural, electronic, and optical properties of the anhydrous 4C16H10Br2O2 Bis (2-Bromobenzoyl) Methane crystals in Pbnc (N°60) and P21/c (N°14) space group are investigated. All computations are determined by a generalized gradient approximation, local density approximation and an ultra-soft pseudopotential. The calculated equilibrium parameters are in good agreement with their available experimental data. This calculation shows that the GGA/PW91 functional overestimate the lattice constant, unlike the LDA/CA-PZ. The Br–C bond distance of 1.856 (1.902) Å is comparable with experimental value of 1.901 (1.896) Å in Pbnc (P21/c) space groups. The direct band gap nature is obtained for both space groups Pbnc and P21/c, since the maximum of the valence band and the minimum of the conduction band are both situated at the YA center