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Effect of Ca substitution on transport and magnetic properties of double‐layered manganite La 1.2 Sr 1.8 Mn 2 O 7
Author(s) -
Reddy Y. S.,
Prashanth Kumar V.,
Rawat R.,
Banerjee A.,
Kistaiah P.,
Vishnuvardhan Reddy C.
Publication year - 2007
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/pssb.200743099
Subject(s) - manganite , magnetoresistance , electrical resistivity and conductivity , variable range hopping , condensed matter physics , magnetization , colossal magnetoresistance , ferromagnetism , metal–insulator transition , atmospheric temperature range , materials science , doping , chemistry , analytical chemistry (journal) , magnetic field , physics , thermodynamics , quantum mechanics , chromatography
The resistivity, magnetoresistance (MR) and magnetization of double‐layered manganite La 1.2 Sr 1.8– x Ca x Mn 2 O 7 (0.0 ≤ x ≤ 0.4) are studied to investigate the effect of substitution of Ca 2+ for Sr 2+ on the transport and magnetic properties. The resistivity data suggest that Ca doping results in the decrease of insulator‐to‐metal transition temperature, T IM . The conduction mechanism above T IM is found to be of Mott variable range hopping type. The highest MR ratios (Δ ρ / ρ 0 ) of 73% ( H = 1.5 T) and 93% ( H = 4 T) are observed for x = 0.3 sample at ∼25 K. The variation of MR with temperature and applied magnetic field is discussed. A secondary transition at T * is observed in all the samples, which may be due to the two‐dimensional short‐range ferromagnetic ordering. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)