Structural, morphological and textural properties of iron manganite (FeMnO3) thick films applied for humidity sensing

Abstract

Iron manganite (FeMnO 3 ) powder with a cubic (bixbyite, ̅ ) crystal structure was obtained by a solid state reaction. Thick film paste (powder + organic vehicles) was screen printed on alumina substrate with test interdigitated PdAg electrodes. Significant porosity (60.6%) composed of macropores (larger than 100 nm) was determined by Hg porosimetry, changing only slightly from the first extrusion run indicating a stable pore system. Hg porosimetry evaluation of thick film samples enabled estimation of true textural parameters of the thick film compared to powder. Impedance response of the thick film sensor was monitored in a humidity chamber in the relative humidity range 30-90%, at room temperature (25 o C) and frequency range from 42 Hz to 1 MHz. At 100 Hz the impedance reduced from 10.41 MΩ to 0.68 MΩ for relative humidity of 30 and 90%, respectively. Analysis of complex impedance using an equivalent circuit showed the dominant influence of grain boundaries. The sensor response and recovery was fast (several seconds) and a relatively low hysteresis value of 2.8% was obtained.

Electrospun Nickel Manganite (NiMn2O4) Nanocrystalline Fibers for Humidity and Temperature Sensing

“…One dielectric relaxation process was noted for complex impedance. This has been noted before for metal oxide semiconductors, including nickel manganite [ 20 , 28 , 55 , 56 ]. Highly conducting grains and the resistive nature of grain boundaries present in nickel manganite contribute to this relaxation process [ 57 ].…”

“…The measured complex impedance spectra (as shown in Figure 6 b at the working temperature of 25 °C) were analyzed using an equivalent circuit consisting of a parallel resistance and constant phase element (CPE), as it was not possible to separate the influence of grain and grain boundary components of the measured impedance, as shown in the inset in Figure 6 b. The CPE element was used, as we expected non-ideal Debye capacitance behavior previously noted for NiMn 2 O 4 synthesized by refluxing nickel oleate and manganese oleate [ 28 ], and other metal oxides, such as FeMnO 3 [ 55 ] or Fe 2 TiO 5 [ 56 ]. Fitting of experimental data to the proposed equivalent circuit was performed using the EIS Spectrum Analyzer Software [ 62 ].…”

Semiconductor Gas Sensors: Materials, Technology, Design, and Application

“…An overview of the investigated metal oxide semiconductors shows that over the years, n-type semiconducting oxides [ 18 ] like tin oxide (SnO 2 ) [ 36 , 37 ], zinc oxide (ZnO) [ 38 , 39 ], anatase (TiO 2 ) [ 40 , 41 ], hematite (α-Fe 2 O 3 ) [ 11 ], and tungsten oxide (WO 3 ) [ 42 , 43 ] and, to a lesser degree, p-type semiconducting oxides such as CuO [ 44 , 45 ], NiO [ 46 , 47 ], and Cr 2 O 3 [ 48 ] or Co 3 O 4 [ 49 ] have been extensively studied. Complex (mixed metal) oxides have also been investigated [ 50 ] such as perovskites [ 51 , 52 ] and cubic spinels such as ferrites [ 11 , 53 , 54 ] and stannates [ 52 ]. Much research has focused on improving the sensing properties of metal oxides, with doping being one of the paths, some examples are Sr-doped Fe 2 O 3 [ 55 , 56 ], Sm-doped CoFe 2 O 4 [ 57 ], and Nb-doped TiO 2 [ 58 ].…”

All-Inorganic p−n Heterojunction Solar Cells by Solution Combustion Synthesis Using N-type FeMnO3 Perovskite Photoactive Layer

“…Iron manganite (FeMnO 3 , FMO) is a mixed perovskite material with the chemical formula ABO 3 , where the Fe atom is placed at the center of a cube formed by eight corner-sharing MnO 6 octahedra ( Habibi and Mosavi, 2017 ). FeMnO 3 has been examined for applications such as lithium-ion batteries, catalysis, humidity sensors, energy storage and antibacterial devices ( Doroftei et al, 2014 ; Cao et al, 2016 ; Cetin et al, 2019 ; Vasiljevic et al, 2020a ; Nikolic et al, 2020 ). A large number of synthesis methods, such as co-precipitation, hydrothermal, ball milling, solid state reaction and sol-gel chemistry, have all been employed for the fabrication of FeMnO 3 materials ( Sundari et al, 2013 ; Doroftei et al, 2014 ; Cao et al, 2016 ; Soni and Pal, 2016 ; Bin et al, 2017 ; Mungse et al, 2017 ; Gowreesan and Ruban Kumar, 2017 ; Saravanakumar et al, 2018 ; Cetin et al, 2019 ; Fix, 2019 ; Lobo and Rubankumar, 2019 ; Vasiljevic et al, 2020a ; Nikolic et al, 2020 ; Vasiljevic et al, 2020b ).…”

“…FeMnO 3 has been examined for applications such as lithium-ion batteries, catalysis, humidity sensors, energy storage and antibacterial devices ( Doroftei et al, 2014 ; Cao et al, 2016 ; Cetin et al, 2019 ; Vasiljevic et al, 2020a ; Nikolic et al, 2020 ). A large number of synthesis methods, such as co-precipitation, hydrothermal, ball milling, solid state reaction and sol-gel chemistry, have all been employed for the fabrication of FeMnO 3 materials ( Sundari et al, 2013 ; Doroftei et al, 2014 ; Cao et al, 2016 ; Soni and Pal, 2016 ; Bin et al, 2017 ; Mungse et al, 2017 ; Gowreesan and Ruban Kumar, 2017 ; Saravanakumar et al, 2018 ; Cetin et al, 2019 ; Fix, 2019 ; Lobo and Rubankumar, 2019 ; Vasiljevic et al, 2020a ; Nikolic et al, 2020 ; Vasiljevic et al, 2020b ). Despite this, not all these techniques are viable to synthesize FeMnO 3 nanomaterials, as there are some drawbacks such as the expense of the source materials, chemical non-uniformity, high impurity, aggregated nanoparticles, and non-stoichiometry of some ferrite systems ( Buonsanti et al, 2012 ; Alves et al, 2013 ; Bennet et al, 2016 ; Skliri, 2018 ).…”