Study of structure, transport, paramagnetic and ferromagnetic properties of La_0.8Sr_0.2Mn_1−xZn_xO₃perovskite manganite

Abstract

La0.8Sr0.2Mn1−xZnxO3 perovskite manganite with x = 0, 0.01, 0.03, 0.05, 0.1, 0.15, 0.3, 0.5 and 0.75 has been prepared by the solid state reaction and investigated by structural, transport and magnetic measurements. The structural characterization of the samples has been done by x-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements. The x-ray powder diffraction results indicate a single phase for 0 < x < 0.5, confirming that zinc is incorporated on the Mn site. The lattice parameters (a, b, c) of this orthorhombic system increase with increasing zinc concentration in the system. According to the SEM images, the grain size of the materials with x > 0.1 decreases with increasing zinc doping levels. The transport measurements show that the insulator-to-metal transition temperature, Tc, decreases with increasing zinc substitution on the Mn site, and the resistivity increases. The Tc variations agree with the magnetic measurement data for x < 0.3. The compound changes from ferromagnetic to paramagnetic for x > 0.3. The possible mechanism behind the effects of zinc doping into the La0.8Sr0.2Mn1−xZnxO3 system involves degradation of the double exchange between Mn3+–O–Mn4+ in this compound.

Young's modulus of some SOFCs materials as a function of temperature

“…It is noteworthy that some insulator-metal and paramagnetic-ferromagnetic transitions were characterized around 75 • C for x = 0.2. 27 The values of the elastic constants at room temperature are reported in Table 2. In order to verify the good reproducibility of Table 1 Porosities of the various LSM samples The impact of the porosity over the elastic modulus is shown in Fig.…”

Structural, electrical and magnetic properties of Sb-doped Pr2/3Ba1/3MnO3 perovskite manganites

“…Also the presence of the dangling bonds at the grain boundary gives rise to different physics when compared to the grain. Several authors have substituted different cations like Fe 3+ , Al 3+ , Ga 3+ , Zn 2+ and Cu 2+ at the Mn-site and have shown that Mn-site substitution severely affects the conduction mechanism as well as the magnetic properties [7][8][9][10][11][12] fewer results exist for higher valent ion substitution at Mn-site to see its effect on the transport properties [13,14]. Substitutions at Mn-sites in manganites, irrespective of their electronic and magnetic nature, lower the ferromagnetic transition temperature but to different extents.…”

Small electroresistance (SER) in bulk La2/3Sr1/3MnO3 below

“…Details of the method used have been given previously by Sotirova et al [6]. The samples were prepared in the form of a disk of 10 mm diameter and 3 mm thickness.…”