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| Author(s): |
Paulo Eduardo Menegasso Filho
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Física Gleb Wataghin |
| Defense date: | 2021-06-09 |
| Examining board members: |
Ricardo Rodrigues Urbano;
Ricardo Luís Doretto;
Jonathas de Paula Siqueira;
José Gerivaldo dos Santos Duque;
Nelson Orlando Moreno Salazar
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| Advisor: | Ricardo Rodrigues Urbano |
| Abstract | |
Systems with collective phenomena of electrons, such as Magnetism and Superconductivity are currently of high interest within Condensed Matter Physics. Among the physical systems investigated in this Thesis, I highlight the heavy fermion compounds of (Ce,Nd)MIn5 (M=Ir, Rh and Co) family. Besides non-conventional superconductivity, the heavy fermions are model systems to exploration of magnetically ordered phases and the Kondo effect. On top of that, there are also the crystalline electric field (CEF) effects that must be taken into account to understand the ground state properties of these systems. Members of the 115s heavy fermions family are convenient since they allow chemical substitution at distinct sites. Our main investigations leading to the result that CEF plays a crucial role on the Ce f-electron orbitals. We propose here a scaling rule that relates the hyperfine coupling between electrons of Ce and nuclei of In with the wavefunction paramenter $\alpha$ of the CEF ground state, which holds true for chemical dopping, hydrostatic pressure and extreme magnetic field in CeMIn5 family. NMR studies on other compounds that resulted in scientific contributions were also mentioned. Thus, on the systems described above, crystallographic, magnetic and thermodynamic characterization experiments provided strong support to the systematic Nuclear Magnetic Resonance (NMR) investigation, by means of the site specific magnetic shift, Knight shift and spin dynamics (spin-spin and spin-lattice relaxation rates) as function of temperature, magnetic field, chemical pressure and anisotropy. Moreover, Electron Spin Resonance (ESR) experiments have been also carried out and the results were very important to complement the NMR results, corroborating with most conclusions and opening up new perspectives for future investigations (AU) | |
| FAPESP's process: | 16/14436-3 - Studies of electronic and magnetic correlation in iron based superconductors and molecular conductors via Nuclear Magnetic Ressonance (NMR) and Quadrupolar (NQR) |
| Grantee: | Paulo Eduardo Menegasso Filho |
| Support Opportunities: | Scholarships in Brazil - Doctorate |