Energy dispersive spectroscopy Entropy Gadolinium High temperature effects Lanthanum compounds Lattice constants Magnetization Microstructure Perovskite Polycrystalline materials Scanning electron microscopy SQUIDs Thermal expansion X ray diffraction analysis Magnetic entropy changes Magnetic refrigeration Magnetocaloric effects (MCE) Room temperature Colossal magnetoresistance
Issue Date:
2005
Publisher:
Journal of Applied Physics
Citation:
Volume 97, Issue 10, Page 1-5
Abstract:
A thorough study of the magnetocaloric effect (MCE) in a colossal magnetoresistive compound of
La0.7 Sr0.3 Mn0.98 Ni0.02 O3 has been made. The large magnetic entropy change of 7.65 Jkg K upon an
applied field of 70 kOe has been found to occur at 350 K, which allows magnetic refrigeration at room
temperature. It is interesting to note that, even in high magnetic fields, the magnetic entropy change versus
temperature distribution is much more uniform than that of gadolinium and several polycrystalline
perovskite manganites, which is desirable for an Ericson-cycle magnetic refrigerator. It is found that such a
small amount (~2%) of substitution of Mn3+ by a magnetic ion (Ni3+ or Co3+) in the perovskite manganite
can favor the spin order and hence the MCE. Undoubtedly, this observation opens a window to explore the
active magnetic refrigeration at high temperatures. ?? 2005 American Institute of Physics.
