Observation of mixed-phase behavior in the Mn-doped cobaltite La0.7Sr0.3Co1-xMnxO3 (x=0-0.5)

• Studies on La0.7Sr0.3Co1-xMnxO3 (x=0-0.5) compounds evidence that the interaction between Mn and Co ions in this system is antiferromagnetic super-exchange and not ferromagnetic (FM) double-exchange (DE). As a result, antiferromagnetism and magnetic glassiness develop steadily with increasing Mn content and the system becomes a spin glass at x similar to 0.1. Analyses of high-field magnetization data indicate that the system consists of two major phases: a metallic FM phase which magnetically saturates in rather low field, and an insulating non-FM phase which has a linear dependence of magnetization on magnetic field. In the low doping regime, the fraction of the non-FM component expands with temperature at the expense of the FM phase and becomes maximal at T-C. Ferromagnetism reappears in highly doped (x >= 0.2) compounds due to the presence of DE interaction between the Mn ions. The small volume fraction of the FM phase derived from the M(H) data in high field region supports the coexistence of insulating and FM behaviors in the highly doped samples. (C) 2009 Elsevier B.V. All rights reserved.

Nyckelord

Perovskite

Cobaltite

Phase separation

Spin glass

TECHNOLOGY

TEKNIKVETENSKAP

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)