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

Abstract

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 Ahmed Dhahri jemai 2000@outlook.fr 1 Laboratoire de la matière condensée et des nanosciences, resistivity under a percolation approach, which is dependent on the phase segregation of a paramagnetic semiconductor and ferromagnetic metallic regions.

Reduced A–B super exchange interaction in zirconium doped cobalt ferrite due to laser irradiation

“…The 1/χ follows the Curie-Weiss law within the high-temperature range [46]. Consequently, the following equations can be used to obtain the Tc, Weiss constant (θ), Curie constant (C), and effective magnetic moment (μ eff ) from the relationship between 1/χ and absolute temperature.…”

Investigation on the structural, magnetic, magnetocaloric and magnetotransport behaviour of La0.7Sr0.3MnO3 manganites synthesised by different routes

“…4,[31][32][33] Different theories have been proposed to explain the low-temperature transport properties like the double exchange (DE) and superexchange (SE) mechanism, Coulomb blockade effect, 34 electron-electron (e-e) interaction, 35,36 inter-granular spin-polarized tunnelling (ISPT), 37 Kondo-like mechanism, weak localization and quantum interference effects (QIEs). 35,36,38,39 It has been proposed that the parent compound LaMnO 3 (ABO 3 structure) is a charge transfer insulator and antiferromagnetic with Mn existing in the +3 oxidation state. 40 The Mn ions enter into a mixed valence state when LaMnO 3 is doped with divalent or tetravalent ions.…”