Efeito magnetocalórico em uma cadeia dupla de spins híbridos

Abstract

The present work studies a hybrid ’2-legged’ spin-ladder chain, with nodal Ising spins and intersitial itinerant electrons which have a hopping amplitude. Initially, there is a brief discussion on some of the most important conceptual aspects concerning the study of magnetic properties in low-dimensional systems. We describe applications of magnetic systems, as well as phenomena such as diamagnetism, paramagnetism, ferromagnetism, ferrimagnetism and antiferromagnetism. Some magnetic effects are also defined, namely the Magnetoresistance and the Magnetocaloric Effect (MCE). This last is later described more profoundly. Afterwards, lowdimensional systems are introduced, with the unidimensional Ising model solution, a discussion on frustrated systems, diamond-chain systems and spin-ladder systems. As a result, we present a review on the study of the magnetic and thermodynamic properties of a hybrid spin ladder realized by Carvalho et. al., as well as how the hopping amplitude and the externallly applied magnetic field change these quantities. Subsequently, the MCE and the Inverse MCE are revisited within this model, with the addition of the isentropic curves’ analysis. Finally, current applications of magnetic refrigeration are presented, and future perspectives for this work.