Magnetocaloric effect in manganites: Metamagnetic transitions for magnetic refrigeration
We present a study of the magnetocaloric effect in La5/8-y Pry Ca3/8 MnO3 (y=0.3) and Pr0.5 Ca0.09Sr0.41 MnO3 manganites. The low temperature state of both systems is the result of a competition between the antiferromagnetic and ferromagnetic phases. The samples display magnetocaloric effect evidenc...
| Autores: | , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2010 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/190887 |
| Acceso en línea: | http://hdl.handle.net/11336/190887 |
| Access Level: | acceso abierto |
| Palabra clave: | MAGNETOCALORIC EFFECT MANGANITE METAMAGNETIC TRANSITION https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| Sumario: | We present a study of the magnetocaloric effect in La5/8-y Pry Ca3/8 MnO3 (y=0.3) and Pr0.5 Ca0.09Sr0.41 MnO3 manganites. The low temperature state of both systems is the result of a competition between the antiferromagnetic and ferromagnetic phases. The samples display magnetocaloric effect evidenced in an adiabatic temperature change during a metamagnetic transition from an antiferromagnetic to a ferromagnetic phase. As additional features, La5/8-y Pry Ca3/8 MnO3 exhibits phase separation characterized by the coexistence of antiferromagnetic and ferromagnetic phases and Pr0.5 Ca0.09Sr0.41 MnO3 displays inverse magnetocaloric effect in which temperature decreases while applying an external magnetic field. In both cases, a significant part of the magnetocaloric effect appears from nonreversible processes. As the traditional thermodynamic description of the effect usually deals with reversible transitions, we developed an alternative way to calculate the adiabatic temperature change in terms of the change of the relative ferromagnetic fraction induced by magnetic field. To evaluate our model, we performed direct measurement of the sample's adiabatic temperature change by means of a differential thermal analysis. An excellent agreement has been obtained between experimental and calculated data. These results show that metamagnetic transition in manganites play an important role in the study of magnetic refrigeration. |
|---|