Banca de DEFESA: ANALINE PINTO VALERIANO BANDEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ANALINE PINTO VALERIANO BANDEIRA
DATA : 30/08/2018
HORA: 10:00
LOCAL: AUDITÓRIO DO DFTE
TÍTULO:

PROPRIEDADES ESTÁTICAS E DINÂMICAS DE SUPER-REDES E MULTICAMADAS QUASIPERIÓDICAS"

PALAVRAS-CHAVES:

spin waves, bilinear coupling, biquadrático coupling, transmittance, static properties, phases, 3D phase diagrams.

PÁGINAS: 166
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

In this study, we investigate the static and dynamics properties of magnetic multilayer and thin film systems, respectively. The propagation of spin waves was investigated in a quasiperiodic superlattice which structure was built according to the so-called Octonacci sequence, composed by two simple cubic ferromagnetic materials interacting through bilinear and biquadratic exchange couplings at their interfaces. The ferromagnetic materials are described by the Heisenberg model, and a transfer matrix treatment is employed, with the calculations performed for the exchange-dominated regime, taking into account the random phase approximation (RPA) to obtain the band and transmittance spectra. In addition, the influence of the biquadratic coupling on the band and transmittance spectra is discussed. We also performed an investigation of the static magnetic properties of nanometric films, with low symmetry crystallographic growth directions ([211] and [321]), by using two quasiperiodic models. For the model 1, the magnetic thin films are stacked quasiperiodically, with the non-magnetic spacers having the same thickness, while for the model 2, the non-magnetic spacers follows the quasiperiodicity, with different thicknesses. For both models the quasiperiodicity is according to the Fibonacci and Octonacci quasiperiodic sequences. The theoretical modelling is based on a realistic magnetic energy taking in account the Zeeman, cubic and uniaxial anisotropy terms, besides the bilinear and biquadratic couplings. From the equilibrium configurations magnetization, magnetoresistance and phase diagrams are obtained

 

MEMBROS DA BANCA:
Presidente - 1345774 - CLAUDIONOR GOMES BEZERRA
Interno - 1519258 - DORY HELIO AIRES DE LIMA ANSELMO
Interno - 2411793 - LEONARDO DANTAS MACHADO
Externo à Instituição - CARLOS HUMBERTO OLIVEIRA COSTA - UFC
Externo à Instituição - JOAO MILTON PEREIRA JUNIOR - UFC