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Magnetization of Manganese Perovskites
Author(s) -
Karpenko Boris V.,
Falkovskaya Lyubov D.,
Kuznetsov Alexandr V.
Publication year - 2008
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/ijc.47.3-4.397
Subject(s) - chemistry , magnetization , superexchange , condensed matter physics , spontaneous magnetization , exchange interaction , spins , heisenberg model , manganese , magnetism , atmospheric temperature range , ion , spin (aerodynamics) , ferromagnetism , magnetic field , quantum mechanics , thermodynamics , physics , organic chemistry
Temperature dependence of spontaneous magnetization at a separate site in the compounds La 1‐x Ca x MnO 3 (0 ⩽ x ⩽ 1) is investigated in the molecular field approximation using a homogeneous model for the magnetic sub‐lattice with allowance for the Heisenberg superexchange and double exchange between nearest neighbors. Unlike with the usual magnets having one type of magnetic ions, in this case there appears a system of equations with two unknowns, mean spins of ions Mn 3+ and Mn 4+ . In the vicinity of the ordering temperature, this system can be solved analytically and the expression for the ordering temperature can be obtained as well. To find the temperature dependence of magnetization in the whole temperature range, we used the exact expression for the double exchange operator containing spin operators under the square root. The numerical solutions were found in this case.