In:
International Journal of Nanoscience, World Scientific Pub Co Pte Ltd, Vol. 10, No. 04n05 ( 2011-08), p. 1019-1024
Abstract:
We report the comparative study on the effect of Ag doping and admixing on the structure and magnetotransport properties of nanophasic La 0.7 Ca 0.3 MnO 3 (LCMO) manganite to resolve the ambiguous issue of Ag substitution at La -site in LCMO manganite. In this context two sets of samples were synthesized, (a) Ag doped La 0.7 Ca 0.3-x Ag x MnO 3 (x = 0, 0.1, 0.15, 0.2, 0.3) and (b) chemically synthesized Ag nanoparticles admixed La 0.7 Ca 0.3 MnO 3 (LCMO + x wt.% Ag-NP , x = 0, 10, 15, 20, 30) and were annealed at 700°C in oxygen ambience. XRD study reveals that for Ag doped nanophasic LCMO samples, orthorhombic LCMO transforms to rhombohedral for x ≥ 0.10 while for Ag admixed LCMO no such transformation occurs, rather Ag is present as a secondary phase. Resistivity decreases for both types of samples, In the case of Ag admixed LCMO it is due to the metallic nature of silver while for Ag doped LCMO, increase in the number of holes as silver being mono valent may be the reason for decrease in resistivity. Both the insulator–metal (T IM ) and ferromagnetic–paramagnetic (T C ) transition temperatures increases with Ag . The corresponding increment in these parameters is ~100 K and ~50 K for 30% Ag doped and for Ag admixed (30%) it is ~60 K and ~15 K respectively than that of pure LCMO. Room temperature magnetoresistance (MR) values are higher (6.8% for x = 0.30) for Ag doped LCMO than that of undoped LCMO (~0.5%).
Type of Medium:
Online Resource
ISSN:
0219-581X
,
1793-5350
DOI:
10.1142/S0219581X11008629
Language:
English
Publisher:
World Scientific Pub Co Pte Ltd
Publication Date:
2011
SSG:
11
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