Regensburg 2002 – wissenschaftliches Programm
MA 19: Spinstrukturen und magnetische Phasenübergänge (incl. Sensoren(19.11) und Messmethoden(19.12-13))
MA 19.9: Vortrag
Donnerstag, 14. März 2002, 17:15–17:30, H23
Magnetocaloric Effects in Perovskite Manganites — •Y. Xu1, M. Meier2, M. R. Koblischka1, and U. Hartmann1 — 1Institute of Experimental Physics, University of Saarbr"ucken, 66041 Saarbr"ucken, Germany — 2Institute of Technical Physics, University of Saarbr"ucken, 66041 Saarbr"ucken, Germany
Synthesis and characterization of La0.67Sr0.33MnO3, La0.67Ba0.33MnO3, and La0.67Ca0.33MnO3 bulk materials are reported. Detailed measurements of the magnetization as a function of temperature and magnetic field for these manganite bulk samples were carried out. Significant entropy changes near the respective Curie temperature are obtained from the magnetization data. The specific heat changes of these samples near their phase transition temperatures are derived from the magnetic measurements. Our results in comparison to the relevant data from the literature are summarized. Perovskite manganites are known as the colossal magnetoresistance materials and may be used as magnetic sensors. Here potential applications in magnetic cooling of these materials at or near room temperatures are evaluated.