Ferromagnetic Resonance in II-VI Diluted Magnetic Semiconductor, ZnxTM1-xO Nanostructures

Gizachew Diga

Abstract

The ferromagnetic resonance in II-VI diluted magnetic semiconductor Zn1 xMnxO was studied theoretically. The model employed to manipulate the Hamiltonian of the system which is the Heisenberg Model. By considering a cloud of electron gas and employing equation of state, the fractions of demagnetization factors was determined. For FMR probes, the sample magnetization results from the magnetic moments of dipolar-coupled but unpaired electrons. The resulting frequency versus magnetization curve is downward parabolic curves which are sharper at tips. This side width sharpening is due to ferromagnetic spin confinement with increasing magnetic ion (Mn2+) concentration. Basic parameters contributing for the resonance formation is dealt with. The angular and magnetic field dependence of resonance frequency is investigated. From the ferromagnetic resonance study, the potential application of Zn1-xMnxO in medical imaging technique will be explored. It is expected that the ferromagnetic absorption frequency is directly proportional to the magnetic flux density B⃗ . Besides, the thermodynamic relation between magnetization and temperature is determined by analysing the Helmholtz free energy. From ferromagnetic resonance studies, it is possible to reveal that Zn1-xMnxO nanoparticles exhibit ferromagnetic behaviour. Determination of properties related with ferromagnetism, typical giant magnetoresistance reveals the potential applications of Zn1-xMnxO nanoparticles medical imaging, nanosensors, biomarkers, magnetic random access memory (MRM) and dynamic random access memory (DRM).

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