TY - JOUR
T1 - Magnetic properties of La0.7Ca0.3MnO3 manganite bulk and nanometer-sized crystals
AU - Rozenberg, E.
AU - Tsindlekht, M. I.
AU - Felner, I.
AU - Sominski, E.
AU - Gedanken, A.
AU - Mukovskii, Ya M.
PY - 2007/6
Y1 - 2007/6
N2 - AC and DC magnetic measurements in temperature interval 5-300 K and at external magnetic field H ≤ 5 T were employed to probe and compare magnetic ordering in bulk and nanometer-sized (15 ± 2 nm) La0.7Ca 0.3MnO3 single crystals. The respective Curie temperatures (TC) ∼ 239 K and 233 K, close to each other are observed in bulk and nano samples. While, their low T spontaneous magnetizations are strongly different, being about 3.6 and 1.2 μB/f.u., respectively. AC susceptibility (χ) of a bulk sample, measured at Hdc = 0, shows a maximum of χ(T) at T ∼ TC. In a contrast, χ(T) of the nano-sample demonstrates a broad maximum far below its TC. In the nano-sample both real and imaginary parts of χ are frequency dependent within the 5-280 K range. In a contrary, the frequency dependence is observed only for imaginary part of χ in bulk crystal. It is concluded that the similar ferromagnetic ground state exists in both considered samples; however, it is strongly frustrated in agglomerated nano particles due to surface magnetic disorder and interparticle interactions.
AB - AC and DC magnetic measurements in temperature interval 5-300 K and at external magnetic field H ≤ 5 T were employed to probe and compare magnetic ordering in bulk and nanometer-sized (15 ± 2 nm) La0.7Ca 0.3MnO3 single crystals. The respective Curie temperatures (TC) ∼ 239 K and 233 K, close to each other are observed in bulk and nano samples. While, their low T spontaneous magnetizations are strongly different, being about 3.6 and 1.2 μB/f.u., respectively. AC susceptibility (χ) of a bulk sample, measured at Hdc = 0, shows a maximum of χ(T) at T ∼ TC. In a contrast, χ(T) of the nano-sample demonstrates a broad maximum far below its TC. In the nano-sample both real and imaginary parts of χ are frequency dependent within the 5-280 K range. In a contrary, the frequency dependence is observed only for imaginary part of χ in bulk crystal. It is concluded that the similar ferromagnetic ground state exists in both considered samples; however, it is strongly frustrated in agglomerated nano particles due to surface magnetic disorder and interparticle interactions.
KW - Magnetic susceptibility
KW - Magnetization processes
KW - Manganese compounds
KW - Nanotechnology
UR - http://www.scopus.com/inward/record.url?scp=34249096165&partnerID=8YFLogxK
U2 - 10.1109/TMAG.2007.894360
DO - 10.1109/TMAG.2007.894360
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AN - SCOPUS:34249096165
SN - 0018-9464
VL - 43
SP - 3052
EP - 3054
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
IS - 6
ER -