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Phase Transitions in the La 0.50 Ca 0.50 MnO 3—γ Manganites
Author(s) -
Trukhanov S.V.,
Troyanchuk I.O.,
Szymczak H.,
Bärner K.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200202)229:3<1417::aid-pssb1417>3.0.co;2-2
Subject(s) - ferromagnetism , antiferromagnetism , condensed matter physics , materials science , spin glass , phase diagram , magnetoresistance , ground state , phase (matter) , cluster (spacecraft) , chemistry , physics , magnetic field , organic chemistry , quantum mechanics , computer science , programming language
The crystal structure, magnetic and electrical properties of the La 0.50 Ca 0.50 MnO 3— γ (0 ≤ γ ≤ 0.50) reduced manganites have been experimentally investigated. It is found that the samples of the La 0.50 Ca 0.50 MnO 3— γ system display a number of phase transitions in the ground state versus γ . The antiferromagnetic state of γ = 0 composition transforms into the inhomogeneous ferromagnetic one at γ = 0.02 which in turn seems to convert into the cluster spin‐glass state at γ ∼ 0.12. At γ = 0.25 an additional ferromagnetic component appears and at γ = 0.30 the fraction of this ferromagnetic component is the highest. At γ ≥ 0.35 the samples seem to be a mixture of the antiferromagnetic phase and ferromagnetic clusters. The strongly reduced sample γ = 0.25 has shown a large magnetoresistance of about 50%. The realized investigations have allowed to construct a hypothetical magnetic phase diagram of the La 0.50 Ca 0.50 MnO 3— γ system. For the explanation of the obtained results the oxygen vacancies are supposed to be non‐randomly distributed over the crystal lattice in the concentration range of 0.12 ≤ γ ≤ 0.25 and trend to be ordered at γ ≥ 0.30 in Sr 2 Fe 2 O 5 –type manner.