Impact of Co2+ on the spectral, optoelectrical, and dielectric properties of Mg0.25Ni0.25Cu0.5−xCoxFe1.97La0.03O4 ferrites prepared via sol–gel auto-combustion route

Abstract

Spinel ferrites are attaining huge importance in the modern era, due to their incredible properties, which means they are widely used in various fields. Therefore, in this paper a costeffective and environmentally friendly preparation of 𝑀𝑔 0.25 𝑁𝑖 0.25 𝐶𝑢 0.5−𝑥 𝐶𝑜 𝑥 𝐹𝑒 1.97 𝐿𝑎 0.03 𝑂 4 (x = 0.0, 0.125, 0.25, 0.375, and 0.5) ferrites via the sol-gel auto-combustion method were carried out. How the structural and functional properties varied with the Cu to Co ratio was studied. It was found that the crystallite size (D) was reduced from 47.2 to 27.6 nm as the Co 2+ increased from x = 0.0 to 0.5. While the two major absorption bands including the higher frequency band (υ1) and lower frequency band (υ2) lie in the range of 573.80 -538.65 cm -1 and 470.37 -405.65 cm -1 belong to the spinel matrix. Five active Raman modes were found in the range of wave number 200 -800 cm -1 corresponds to the sublattices of the spinel structure.The optical bandgap increased from 0.85 eV to 1.33 eV for x = 0.0 to x = 0.25 and then observed optical band gap was 1.15 eV and 1.46 eV for x = 0.375 to x = 0.5. The resistivity (ρ) was minimum for Co 2+ concentration x = 0.25 at low temperature, while at high temperature the resistivity (ρ) was maximum for Co 2+ doping x = 0.25. The temperature coefficient of resistance percentage (TCR %) was −2.66%/K at 513 K for x = 0.25, as shown in the graphical abstract.At lower frequencies, the impedance was observed maximum for Co 2+ doping x = 0.125 and minimum for x = 0.375. These findings indicate that the as-prepared ferrites are a potential candidate for optoelectrical and bolometric devices.

Summerfield scaling model and electrical conductivity study for understanding transport mechanisms of a Cr3+ substituted ZnAl2O4 ceramic

“…A negative TCR value −2.7% K −1 is found at 560 K. ZnAl 1.95 Cr 0.05 O 4 compound has a higher TCR value compared to other values published in other works. 85 This result shows that our compound is a good candidate for uncooled infrared bolometric applications and infrared detectors.…”

Tailoring of Structural, electrical, and dielectric properties of Mg-Mn-Bi nanoferrites with addition of Zn

“…The variation in vibrational bonds due to Zn concentrations is shown in Table 2. The vibration modes E g , 3T 2g , 2T 2g , fit for octahedral site and A 1g , and 1T 2g belong to tetrahedral site [18][19][20]. The strong disparity in vibrational bond related to tetra site confirms the replacement of Zn on Mn.…”

Synthesis and characterizations of nickel doped Co-Zn-Y ferrites

“…5 that activation energy for the paramagnetic region is greater than the activation energy for the ferrimagnetic region. This may be ascribed to the ordered magnetic domains in the ferrimagnetic region while randomly oriented magnetic domains in the paramagnetic region so more energy are required for the ions to jump from one cation to another [30].…”