Banca de DEFESA: DIEGO BERNABE ORTIZ SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : DIEGO BERNABE ORTIZ SILVA
DATE: 26/07/2024
TIME: 09:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

MICRO MICROMAGNETIC SIMULATION IN DISC AND ELLIPSOID ARRANGEMENTS

KEY WORDS:

Microlithography. DWL. Magnetic arrays. Permalloy. OOMMF

PAGES: 82
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

The properties of arrays of objects have gained much attention from the scientific community due to their applications and to academic problems that are still unsolved. An array can be studied magnetically using microscopy techniques. Numerical approximations can also be applied to obtain theoretical predictions by solving the equations of micromagnetism. Especially when dealing with large arrays, whose objects present interactions, doubts arise regarding the effects of the dipolar energy of interaction between objects and the boundary conditions to be applied when solving the problem. When dealing with micrometric objects, different magnetization configurations can arise within the elements that form the array. In this work, we present the fabrication of arrays of disks and ellipsoids arranged in a square arrangement. The responses obtained in magnetization measurements with different directions of the external field allow us to study how each array behaves. The measurements were performed by applying an external magnetic field in the plane of the two-dimensional array and changing its orientation in relation to the main directions. The objects obtained here were manufactured with optical writing using the DWL66 system and sputtering deposition of Permalloy. The deposition of soft magnetic material facilitates the disregard of magnetocrystalline anisotropy effects. Magnetic measurements were performed using vibrating sample magnetometry (VSM), which reveal soft ferromagnetic behavior at room temperature, in agreement with the simulations. The morphological characterization of the samples was performed by optical microscopy and scanning electron microscopy (SEM). For the micromagnetic simulations, we used the Object Oriented Micromagnetism Framework (OOMMF) code to study the magnetization process of the objects. The code is based on the Landau-Lifshitz-Gilbert equation to simulate the configuration of the magnetic moments and calculate the magnetization energy of the microstructures. The results are compared with the experimental data. The coercive fields have an error of only 2%, possibly due to temperature considerations. The magnetization diagrams show the presence of multiple magnetization mechanisms in this system.

COMMITTEE MEMBERS:
Presidente - 2457389 - EDUARDO PADRON HERNANDEZ
Externo à Instituição - ALVARO ANTONIO OCHOA VILLA - IFPE
Externo à Instituição - JOSE ANGELO PEIXOTO DA COSTA - IFPE
Externo à Instituição - RAMÓN RAUDEL PEÑA GARCIA - UFRPE
Externo à Instituição - YUSET GUERRA DAVILA - UFAL