Siruguri, V and Gutiérrez, J and Barandiaràn, J M and Làzpita, P and Singh, Brajendra and Sahu, Ranjan K and Sundar Manoharan, S and Henry, P and Mondelli, C (2006) Neutron diffraction evidence for double exchange coupling in Ru-substituted La0.6Pb0.4Mn1−xRuxO3, 0x0.5. Physica B: Condensed Matter, 385-386 (1). pp. 408-410.
Restricted to NML users only. Others may use ->
Double exchange (DE)-mediated ferromagnetism in manganites, in which the Zener pair (Mn3+/Mn4+) is a key factor, is marked by the coexistence of the magnetic transition and the metal-insulator transition, thus distinguishing itself from superexchange (SE)-mediated ferromagnetism. Through detailed magnetization, transport and XAS studies, it was proposed by some of us that a unique magnetic pair-making effect occurs in Ru-substituted La0.6Pb0.4Mn1−xRuxO3 by virtue of variable valency of Ru and Mn. Ru ion, exhibiting a variable valency of Ru4+ and Ru5+, governs the DE-mediated coupling by initiating a magnetic pair-making effect with Mn3+ and Mn4+ states. Neutron diffraction measurements carried out on these compounds in the temperature range 4.2–500 K reveal the microscopic nature of magnetic ordering. Data obtained, in conjunction with data from other experimental techniques above, show that (i) Ru participates in the DE interaction with Mn for x0.4, (ii) there is a weakening of DE due to depletion of Ru5+ for x>0.4, and (iii) SE ferromagnetic interactions are favored for x>0.4.
|Uncontrolled Keywords:||Neutron diffraction; Exchange and superexchange interactions; Colossal magnetoresistance|
|Divisions:||Material Science and Technology|
|Deposited By:||Dr Ranjan K Sahu|
|Deposited On:||21 Dec 2009 17:10|
|Last Modified:||09 Feb 2012 16:45|
Repository Staff Only: item control page