Influence of Na Addition on Magnetic and Magnetocaloric Effects of La0.67Pb0.13Na0.2MnO3 Ceramics

• Published in: Journal of superconductivity and novel magnetism Vol. 29; no. 10; pp. 2543 - 2551
• Main Authors: Zaidi, Asma, Dhahri, Ahmed, Dhahri, J., Hlil, E. K., Zaidi, M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-10-2016; Springer Verlag
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Magnetic Materials; Magnetism; Original Paper; Physics; Physics and Astronomy; Strongly Correlated Systems; Superconductivity; Na-doped manganites; Magnetocaloric effect; Electrical transport; Griffiths phase
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-016-3573-4

Structural, magnetic, magnetocaloric, and electrical properties are reported for mixed-valence manganite La
0.67
Pb
0.13
Na
0.2
MnO
3
. X-ray diffraction reveals that the sample crystallizes in the rhombohedric structure with the R-3c space group. The magnetic properties of the polycrystalline La
0.67
Pb
0.13
Na
0.2
MnO
3
compound are discussed in detail, based on the susceptibility, magnetization, and isotherm. The sample presents a ferromagnetic property with
T
C
= 275 K and a Griffiths phase at
T
G
= 325 K which gives the existence of ferromagnetic clusters in the paramagnetic domain. A large deviation is usually observed between field cooled (FC) and zero field cooled (ZFC).
M
(
T
) is a low temperature below the blocking temperature. At 40 K, a spin-glass or a cluster-glass state is seen to arise from a ferromagnetic state. This is caused by the competition between the antiferromagnetic and ferromagnetic interactions. The electrical properties show the presence of a metal–semiconductor transition at
T
M−Sc
. To understand the dependence of disorder with the transport mechanism, we used the phenomenological equation for resistivity under a percolation approach, which is dependent on the phase segregation of a paramagnetic semiconductor and ferromagnetic metallic regions.