2 research outputs found
EVALUATION REPORT ON THE IMPLEMENTATION OF THE 2011-2016 REPUBLIC OF MOLDOVA JUSTICE SECTOR REFORM STRATEGY AND ACTION PLAN: PILLAR 6.4.3 âCAPACITY BUILDING OF INSTITUTIONS IN CHARGE OF THE DEPRIVATION OF LIBERTY TO PREVENT AND COMBAT TORTURE AND ILL-TREATMENTâ, AND 6.4.5 âEFFECTIVELY COMBATTING ACTS OF TORTURE AND ILL-TREATMENT
Influence of La3+ on structural, magnetic, dielectric, electrical and modulus spectroscopic characteristics of single phase CoFe2âxLaxO4 nanoparticles
In this work, we have studied the influence of La3+ substitution on structural, magnetic, dielectric, electrical and modulus spectroscopic characteristics of cobalt ferrite nanoparticles synthesized by starch-assisted solâgel combustion method. The powder X-ray diffraction analysis confirms the formation of single-phase CoFe2âxLaxO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20) spinel ferrite nanoparticles. Raman spectroscopy study also reveals the formation of single phase spinel ferrite crystal structure. The morphological feature of synthesized ferrite nanoparticle was observed by scanning electron microscopy that demonstrate formation of spherical nanoparticles with grain size 10â50 nm. The presence of constituentâs, i.e., Co, Fe and La were authenticated by energy dispersive X-ray analysis. The magnetic parameters are measured by employing vibrating sample magnetometer. The saturation magnetization decreases with La3+ substitution, whereas coercivity shows anomalous behaviour. Cation redistribution in spinel ferrite nanoparticles are confirmed by X-ray photoelectron spectroscopy. The variation of dielectric constant (Ï”âČ, Ï”Êș), loss tangent (tanÎŽ), ac conductivity (Ï), electric modulus (MâČ, MÊș) and impedance (ZâČ, ZÊș) as a function of La3+ ion concentration and frequency has been investigated. The dielectric constant and ac conductivity increases with increase of La3+ substitution, whereas dielectric loss tangent exhibits anomalous behaviour. The modulus spectra reveal two semicircles associated with grain and grain boundary effects. The coleâcole plots in modulus formalism show that the electrical characteristics contribute from both the grains and grain boundaries. Modulus spectra suggest that the distribution of relaxation times and conduction mechanism are influenced by La3+ ion substitution in cobalt ferrite nanoparticles. © 2017, Springer Science+Business Media New York.Ministry of Education, Youth and Sports of the Czech Republic-Program NPU I [LO1504