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CONDENSED MATTER
Critical behavior of La$_{0.825}$Sr$_{0.175}$MnO$_{2.912}$ anion-deficient manganite in the magnetic phase transition region
S. V. Trukhanova,
A. V. Trukhanovb,
A. N. Vasilievc,
A. Maignand,
H. Szymczake a Institute of Solid State Physics and Semiconductors NASB
b Vitebsk State University named after P. M. Masherov
c M. V. Lomonosov Moscow State University, Faculty of Physics
d Laboratoire CRISMAT, ISMRA, 14050 Caen Cedex, France
e Institute of Physics, Polish academy of sciences, 02-668 Warsaw,
Poland
Abstract:
For La
0.825 3+ Sr
0.175 2 +Mn
3+O
2.912 2− anion-deficient manganite, the specific magnetization, the dynamic magnetic susceptibility, and the heat capacity are investigated. This material is found to be an inhomogeneous ferromagnet below the Curie point
T C ≈ 122 K, which is much lower than the Curie point determined for the stoichiometric composition (
T C ≈ 268 K). An increase in magnetic field by two orders of magnitude leads to an increase in the Curie temperature by Δ
T ≈ 12 K. The presence of oxygen vacancies leads to the frustration of a part, namely,
V fr ≈ 22%, of the indirect Mn
3+-O-Mn
3+ exchange interactions, but the spin glass state is not realized. The ferromagnetic matrix of the material under study is characterized by a scatter in the exchange interaction intensities. The heat capacity is found to exhibit an anomalous behavior. Based on the Banerjee magnetic criterion, it is established that the ferromagnet-paramagnet transition observed for La
0.825 3+ Sr
0.175 2+ Mn
3+O
2.912 2− anion-deficient manganite is a second-order thermodynamic phase transition. The mechanism and origin of the critical behavior of the system under investigation are discussed.
PACS:
75.30.Kz, 75.30.Vn,
75.50.Dd