Banca de QUALIFICAÇÃO: FRANCISCO ANDREÁZIO LÔBO DE ANDRADE

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : FRANCISCO ANDREÁZIO LÔBO DE ANDRADE
DATA : 28/01/2022
HORA: 16:00
LOCAL: Sala virtual
TÍTULO:

Domain wall release at FM/AFM interface defects by spin-polarized current

PALAVRAS-CHAVES:

Spin polarized current; domain walls, vicinal surfaces

PÁGINAS: 50
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
SUBÁREA: Física da Matéria Condensada
ESPECIALIDADE: Materiais Magnéticos e Propriedades Magnéticas
RESUMO:

With the growing demand for data generation, storage and processing, there is a continuous search for recording media with greater data storage capacity and processing speed. In this context, researchers worldwide have been investing in alternatives to current recording media. Racetrack Memory is an emerging technology candidate to replace current memories. Researchers expect this type of non-volatile solid-state memory to have a higher storage capacity than currently available memories. The Racetrack Memory device is based on the stabilization and controlled motion of magnetic domain walls in nanowires by the spin-polarized current. Our work comprises a theoretical study of releasing magnetic domain walls in ferromagnetic nanostripes (Py or Fe) coupled to a vicinal antiferromagnetic substrate of two sub-grids (FM/AFM) by the spin-polarized current. Previous studies show that domain walls are trapped in interface steps perpendicular to the easy axis of the antiferromagnet, separating terraces with opposite interface exchange fields. In the absence of an applied external field, the center of the domain wall is on the interface step. This work will consider a spin-polarized current applied along the easy antiferromagnetic axis. Here, the spin-transfer torque occurs only in the domain wall region. We will investigate the minimum intensity of the spin-polarized current density (J) to release domain walls in Fe/AFM and Py/AFM. Preliminary results show the current density limit to release a magnetic domain wall trapped in a ferromagnetic nanostripe coupled to a uniaxial vicinal antiferromagnetic substrate of two vicinal subnets, with a single defect, is a function of the interface field strength. Furthermore, we will carry out a systematic study on how the geometric parameters of the system change the threshold current density for the release of magnetic domain walls. Our work also investigates the release of a train of domain walls in ferromagnetic nanoribbons (Py or Fe), coupled to a vicinal antiferromagnetic substrate of two sub-grids (FM/AFM), by the spin-polarized current. In this context, it will be investigated whether the interaction between domain walls alters or not the intensity of the threshold spin-polarized current for the release of the magnetic domain wall train.

MEMBROS DA BANCA:
Externo ao Programa - 12216 - LEONARDO LINHARES OLIVEIRA
Externo à Instituição - SERGIO MURILO DA SILVA BRAGA MARTINS JUNIOR - UEMA
Externa à Instituição - RAFAELA MEDEIROS DE SOUZA - FURG