Synthesis and characterization of nitrogenated MgB2 superconducting pellets

• Grant number: 25/20554-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2026
• End date: February 28, 2027
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Lucas Barboza Sarno da Silva
• Grantee: Betina Brun
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

Magnesium diboride (MgB¿) is a superconductor with a critical temperature (Tc) around 39 K, whose discovery in 2001 spurred intense research due to its potential for technological applications. Despite the advances, its transport properties can still be significantly optimized. Improvement strategies include enhancing grain connectivity, increasing densification, structural and chemical modification, as well as reinforcement of magnetic flux pinning. A promising approach is combined doping, using a substitutional dopant to alter the electronic structure and another particulate or interstitial dopant to act as a flux pinning center. This project proposes to investigate the effects of nitrogen (N) incorporation into MgB¿ superconducting pellets through two experimental routes: sintering in a nitrogen-rich atmosphere and the use of the precursor compound BN (boron nitride). The objective is to understand the doping mechanisms, defect generation, and their influence on structural properties, critical current density (Jc), and upper critical field (Hc¿). The samples will be obtained by high-energy ball milling, cold compaction, and heat treatment under continuous nitrogen flow. Sintering under positive isostatic pressure in a nitrogen atmosphere will also be analyzed. Characterizations will be performed using X-ray diffraction, scanning electron microscopy, and magnetic measurements. By the end of the study, it is expected to establish an efficient production route for the incorporation of nitrogen into the MgB¿ superconducting matrix, either as substitutional and/or interstitial doping, thus modifying the superconducting properties of the material. (AU)