| Journal: | Brazilian journal of physics |
| Database: | PERIÓDICA |
| System number: | 000392506 |
| ISSN: | 0103-9733 |
| Authors: | Souza, Mariano de1 Paupitz, Ricardo1 Seridonio, Antonio1 Lagos, Roberto E1 |
| Institutions: | 1Universidade Estadual Paulista "Julio de Mesquita Filho", Instituto de Geociencias e Ciencias Exatas, Rio Claro, Sao Paulo. Brasil |
| Year: | 2016 |
| Season: | Abr |
| Volumen: | 46 |
| Number: | 2 |
| Pages: | 206-212 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, analítico |
| English abstract | In the field of condensed matter physics, specific heat measurements can be considered as a pivotal experimental technique for characterizing the fundamental excitations involved in a certain phase transition. Indeed, phase transitions involving spin (de Souza et al. Phys. B Condens. Matter 404, 494 (2009) and Manna et al. Phys. Rev. Lett. 104, 016403 (2010)), charge (Pregelj et al. Phys. Rev. B 82, 144438 (2010)), lattice (Jesche et al. Phys. Rev. B 81, 134525 (2010)) (phonons) and orbital degrees of freedom, the interplay between ferromagnetism and superconductivity (Jesche et al. Phys. Rev. B 86, 020501 (2012)), Schottkylike anomalies in doped compounds (Lagos et al. Phys. C Supercond. 309, 170 (1998)), electronic levels in finite correlated systems (Macedo and Lagos J. Magn. Magn. Mater. 226, 105 (2001)), among other features, can be captured by means of high-resolution calorimetry. Furthermore, the entropy change associated with a first-order phase transition, no matter its nature, can be directly obtained upon integrating the specific heat over T , i.e.,C(T )/T , in the temperature range of interest. Here, we report on a detailed analysis of the two-peak specific heat anomalies observed in several materials. Employing a simple multilevel model, Mariano de Souza mariano@rc.unesp.br 1 Departamento de F´ısica, IGCE, Unesp - Univ Estadual Paulista, 13506-900, Rio Claro, SP, Brazil 2 Departamento de F´ısica e Qu´ımica, Unesp - Univ Estadual Paulista, 15385-000, Ilha Solteira, SP, Brazil 3 Present address: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Linz, Austria varying the spacing between the energy levels i = (Ei − E0) and the degeneracy of each energy level gi, we derive the required conditions for the appearance of such anomalies. Our findings indicate that a ratio of 2/1 ≈ 10 between the energy levels and a high degeneracy of one of the energy levels define th |
| Disciplines: | Física y astronomía |
| Keyword: | Física de materia condensada, Calor específico, Función de partición, Efectos de correlación |
| Keyword: | Physics and astronomy, Condensed matter physics, Specific heat, Partition function, Correlation effects |
| Full text: | Texto completo (Ver PDF) |
