Magnetoimpedance, magnetoresistance, and magnetic properties of nanometric CMR manganites

Abstract

The effects of nanometric grain size (ϕ=14–28nm) modulation on the behavior of magnetoimpedance (MI), magnetoresistance, and magnetic properties of chemically synthesized a series of single-phase soft ferromagnetic nanocrystalline colossal magnetoresistance La0.7Sr0.3MnO3 (LSMO) manganites at room temperature have been reported. From the frequency and magnetic filed dependent MI measurement it is found that the MI percent increases with the increase in nanometric grain size (ϕ) for this series of samples. This behavior has been explained in the light of classical electrodynamics, which relates this effect with the dependency of skin depth on external magnetic field and applied ac signal frequency. Room temperature low field magnetoresistance (LFMR) study of this series of LSMO nanoparticles has also been carried out for comparison.

Magnetic Properties of Interacting La0.67Sr0.33MnO3 Nanoparticles

“…By increasing the particle size, the spontaneous magnetization and curvature are increased which indicates that the magnetic order in the samples are increased. This behavior has been also reported for LSMO nanoparticles [26,27].…”

“…From Fig. 4, Arrott plot shows a strong convex curvature with a finite spontaneous magnetization which is a signature of ferromagnetic phase of the samples [26,27]. Spontaneous magnetization can be estimated by linear fitting of the high magnetic field part of the M 2 -H/M curve and intercepts it with the M 2 axis.…”

Superparamagnetic behavior of La0.67Sr0.33MnO3 nanoparticles prepared via sol–gel method

“…8. ABK plot shows a strong convex curvature with a finite spontaneous magnetization which is a signature of ferromagnetic phase of S2 sample [27,28]. Due to the existence of size distribution, the magnetic nanoparticles of the S2 sample have different blocking temperatures.…”

Evidence of non-stoichiometry effects in nanometric manganite perovskites: influence on the magnetic ordering temperature

“…In contrast, the evolution of Curie temperature claimed for these new materials was highly controversial. Some authors reported a decrease of T C with decreasing crystallite size either on La 1Àx Ca x MnO 3 16,20 or La 1Àx Sr x MnO 3 8,17,19,23,24,26,28 samples with x close to 0.3. This evolution was often interpreted in terms of MDL which contributed to destabilize the magnetic order.…”