Regensburg 2002 – wissenschaftliches Programm

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MA: Magnetismus

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 La_0.67Sr_0.33MnO₃, La_0.67Ba_0.33MnO₃, and La_0.67Ca_0.33MnO₃ 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.