Synthesis of HfV2Ga4 polycrystalline samples and experimental characterization of their unconventional superconducting propertie

Author(s)

Frederico Benedetto Santos

• Document type: Doctoral Thesis
• Press: Lorena.
• Institution: Universidade de São Paulo (USP). Escola de Engenharia de Lorena (EEL/ASDI)
• Defense date: 2021-03-24

Examining board members

Antonio Jefferson da Silva Machado; Ausdinir Danilo Bortolozo; Enzo Granato; Maria José Ramos Sandim

• Advisor: Antonio Jefferson da Silva Machado

Abstract

In this work a criterion to separate conventional and unconventional supercondutors will be presented, moreover the structural and superconducting properties of the ternary compound HfV2Ga4 will be shown and discussed. This material structure was determined by X ray diffractometry and its chemical composition by energy dispersive spectroscopy (EDS), the superconducting properties were defined by magnetic susceptibility, electrical resistivity, specific heat and muon spic rotation and relaxation. Furthermore, first principles calculation were performed bringing to discussion important data on HfV2Ga4 electronic and band structure. Disagreements regarding BCS theory were found mainly in the lower and uper critical field diagrams and specific heat measurements as function of temperature. Finally, μSR results shown that the superconducting gap can be described by a (s+d) wave function, this set of results allow us to categorize this material as a multiband superconductor. (AU)

• FAPESP's process: 16/11565-7 - Investigation of the superconductivity and magnetism in compounds that crystallize on the YbMo2Al4 and IrIn3 prototype
• Grantee: Frederico Benedetto Santos
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)