Banca de DEFESA: RAFAEL MENDES FRANCISCO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RAFAEL MENDES FRANCISCO
DATE: 06/03/2023
TIME: 09:30
LOCAL: on-line
TITLE:

EFFECTIVE FIELD THEORY IDENTITY FOR THE STUDY OF FIRST ORDER PHASE TRANSITIONS IN SEMI-CLASSIC SPINS MODELS

KEY WORDS:

Semi-classical spin systems; First-order phase transitions; Effective-Field Theory; Borophene; Spin-Crossover.

PAGES: 87
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUBÁREA: Física da Matéria Condensada
SPECIALTY: Materiais Magnéticos e Propriedades Magnéticas
SUMMARY:

With the aim of studying first-order phase transitions of semi-classical spin models, in this work, an identity based on the Effective Field Theory (EFT) from the differential operator technique is proposed. By means of the Maxwell construction for the free energy of thermodynamic systems, the Effective Field Theory Identity (EFTI) can be used for calculating points in phase diagrams in which two distinct states present the same free energy value. First, the EFTI is applied to a generalization of the Blume-Capel model in order to present its effectiveness and make the procedures clearer. Following these calculations, the EFTI will be applied to two technological material structures that present first-order phase transitions. For a spin-3/2 Borophene structure, phase diagrams are obtained by means of the EFT and of the Mean-Field Theory (MFT), with the EFTI being used in the calculations of first-order phase transition lines in the EFT context. Finally, the EFTI is applied to a spin-1/2 system that presents first-order
phase transitions within the phenomenon known as "spin-crossover". The outcomes for this system are compared to some results present in the literature.

BANKING MEMBERS:
Presidente - 1716159 - JANDER PEREIRA DOS SANTOS
Interno - 1527524 - WAGNER SOUZA MACHADO
Interno - 1217987 - ANDRE LUIZ MOTA
Externo à Instituição - FRANCISCO CESAR DE SA BARRETO - UFMG
Externa à Instituição - MARIA EUGÊNIA SILVA NUNES - UFOP