Banca de QUALIFICAÇÃO: MATEUS SOUZA DUTRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : MATEUS SOUZA DUTRA
Data: 11/08/2026
HORA: 14:00
LOCAL: R601-3 (Bloco A, Torre 3, 6o Andar)
TÍTULO:

Engineering magnetism in EuZn2P2 through chemical substitution and optical excitation

PÁGINAS: 100
RESUMO:

Rare-earth-based quantum materials have attracted considerable attention due to the strong coupling among charge, spin, and lattice degrees of freedom, enabling the control of their physical properties through external stimuli. Among these materials, the magnetic semiconductor EuZn2P2 stands out for exhibiting antiferromagnetic ordering, a narrow band gap, and colossal magnetoresistance. In this thesis, two complementary strategies to modify its magnetic properties are investigated: chemical substitution and optical excitation.
The spin dynamics of EuZn2P2 single crystals were investigated by Electron Spin Resonance (ESR) under illumination with different wavelengths. The results demonstrate that the photoinduced response depends strongly on the wavelength of the incident radiation, indicating that distinct optical excitations affect spin relaxation through different mechanisms. These findings suggest that the magnetic response is governed by the dynamics of photogenerated carriers created during photoexcitation, giving rise to a possible photomagnetic effect.
As a complementary approach, the partial substitution of Zn by Cd and Ga was investigated. Cd substitution induces an expansion of the crystal lattice and suppresses the Néel temperature, whereas Ga substitution modifies the electronic transport properties while preserving the narrow-gap semiconducting character. These changes were characterized by X-ray diffraction, specific heat, magnetization, electrical resistivity, magnetoresistance, ESR, and terahertz time-domain spectroscopy.
Overall, the results demonstrate that the magnetic and electronic properties of EuZn2P2 can be effectively tuned through both chemical substitution and optical excitation, establishing this compound as a promising platform for exploring the interplay among light, electronic transport, and magnetism in correlated magnetic semiconductors.

 

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1762413 - LUCIANO SOARES DA CRUZ
Membro Titular - Examinador(a) Interno ao Programa - 1545447 - MARCOS ROBERTO DA ROCHA GESUALDI
Membro Titular - Examinador(a) Interno ao Programa - 3501735 - VITOR HUGO PASCHOAL
Membro Suplente - Examinador(a) Interno ao Programa - 3420345 - CARLOS AUGUSTO MERA ACOSTA