•Larger ionic radii Samarium and Gadalonium doped Manganese Zinc Ferrite Nanoparticles Prepared by Solution Combustion Method.•The average crystallite size and lattice parameter varies with Sm3+ and ...Gd3+ ions concentration due to small difference in ionic radius of Sm3+ (0.964 Å) ions, Gd3+ (0.938 Å) ions and Fe3+ (0.645 Å) ions.•The internal strain found in the range 0.55 × 10-2 to 1.09 × 10-2 (%).•Drastic change was observed in saturation magnetization, remanent magnetization and reduce remanence and are found 44.16 to 5.805 emu/g, 24.46 to 0.093 emu/g and 0.5991 to 0.016.
Nanoparticles of Mn0.5Zn0.5Fe2O4, Mn0.5Zn0.5Fe1.95Sm0.05O4 and Mn0.5Zn0.5Fe1.9Gd0.05Sm0.05O4 ferrites are prepared by solution combustion method and characterized to comprehend their structural, microstructural and magnetic properties. The single-phase formation and spinel cubic structure of the samples analyzed by XRD method. The average crystallite sizes were found in the range 10.26 to 16.68 nm. The lattice parameters were found in the range 8.4157 to 8.4508 Å. The particle size was studied by using TEM micrographs and found to be in nano range. The results are good agreements with XRD results. A strong correlation between the size of the particle with respect to the Sm3+ and Gd3+ content has been identified using TEM micrographs. The M-H loop of Mn0.5Zn0.5SmxGdyFe2-(x+y)O4 (where x = 0, y = 0; x = 0.05, y = 0; x = 0.05, y = 0.05) nanoparticles exhibit ferromagnetic nature with saturation magnetization and coercivity. The M-H loop of Mn0.5Zn0.5Fe2O4 nanoparticles exhibit a high saturation and remanent magnetization. The saturation magnetization and remanent magnetization found in the range 44.16 to 5.805 emu/g and 24.46 to 0.093 emu/g, respectively. The saturation and remanent magnetization decreases after Sm3+ and Gd3+ substitution on Fe- site in Mn0.5Zn0.5Fe2O4 is because of the distinction in the cation distribution at tetrahedral site and octahedral site. Meanwhile, experiments demonstrate that the solution combustion method has significant effect on structure and magneticbehavior of the preparedferritenanoparticles.
Humidity sensing properties of NiFe
2
O
4
/CoCr
2
O
4
nanocomposites ceramics were reported for the first time through chemical synthesis and mechanical mixing methods. The interaction of CoCr
2
O
4
...and NiFe
2
O
4
was analyzed through X-ray diffraction, and the morphology of the samples was studied with Field emission scanning electron microscopy(FESEM). The results indicate that nonmetal elements act as interstitial ones to form the composite. As the amount of NiFe
2
O
4
increased, the morphology of the nanocomposites changed from near-spherical to irregular cube-like shapes, with their particle sizes increasing over 10 nm. We studied elemental analysis using the EDX technique. Additionally, the resistance and humidity sensing responses become more noticeable, with desorption occurring slower than adsorption. The sensor takes 10 s to react and 15 s to recover. These findings provide a potential approach to creating large-scale chromate–ferrite composites and improving their structural, morphological, and humidity sensing properties, making them excellent candidates for humidity sensor applications.
Rare earth-doped ferrites are exhibiting remarkable surface phenomena. Wherein the process of adsorption is most significant. Humidity sensors are the realization of an adsorption mechanism. ...Therefore, rare earth-doped ferrites are suitable for humidity sensor applications. Considering this fact, in the present work, Holmium(Ho
3+
) Mn-Bi ferrites are prepared by the solution combustion method with the general formula Mn
0.95
Bi
0.05
Fe
2-x
Ho
x
O
4
(
x
= 0 to 0.03). The effect of holmium doping on the structural, microstructural, magnetic, and humidity properties was analyzed. The X-ray diffraction revealed the formation of a cubic spinel structure. The average crystallite size was obtained by using the Scherrer method, with a range of 7 to 13 nm. The presence of nanoparticles in samples increases the surface area required to favor adsorption mechanisms in the samples. The Scanning Electron Microscopy micrographs showed the surface morphology with the presence of pores, holes, and on their surfaces. Vibrating sample magnetometry confirmed superparamagnetic behavior. The saturation magnetization (M
s
) was found to decrease with an increase of Ho
+3
content in the samples. We observed the decrements of resistance with the increment of relative humidity from 11 to 97% relative humidity and the increase of sensing response with an increase in relative humidity. At 54% relative humidity, maximum humidity hysteresis is found to be 2%. The sensing response time and recovery time were recorded to be 79 s and 91 s, respectively. The difference between sensing response and recovery time is small. These kinds of samples may be used in applications of sensing material.
Comprehension of chemical bonding and its intertwined relation with charge carriers and heat propagation through a crystal lattice is imperative to design compounds for thermoelectric energy ...conversion. Here, we report the synthesis of large single crystal of new p‐type cubic AgSnSbTe3 which shows an innately ultra‐low lattice thermal conductivity (κlat) of 0.47–0.27 Wm−1 K−1 and a high electrical conductivity (1238 – 800 S cm−1) in the temperature range 294–723 K. We investigated the origin of the low κlat by analysing the nature of the chemical bonding and its crystal structure. The interaction between Sn(5 s)/Ag(4d) and Te(5p) orbitals was found to generate antibonding states just below the Fermi level in the electronic band structure, resulting in a softening of the lattice in AgSnSbTe3. Furthermore, the compound exhibits metavalent bonding which provides highly polarizable bonds with a strong lattice anharmonicity while maintaining the superior electrical conductivity. The electronic band structure exhibits nearly degenerate valence‐band maxima that help to achieve a high Seebeck coefficient throughout the measured temperature range and, as a result, the maximum thermoelectric figure of merit reaches to ≈1.2 at 661 K in pristine single crystal of AgSnSbTe3.
The existence of p‐d and s‐p antibonding states near the Fermi level as well as metavalent bonding provide an ultra‐low lattice thermal conductivity while maintaining a high electrical conductivity, resulting in a high thermoelectric performance of the cubic AgSnSbTe3 single crystal.
Herein we report the effect of samarium (rare earth metal) doping on the morphological, structural, optical, magnetic, dielectric, and electrical properties of copper–iron oxide ferrite composites ...CuFe
2−
x
Sm
x
O
4
(
x
= 0, 0.05, 0.075, and 0.1) (abbreviated as SCFO). The CuFe
2−
x
Sm
x
O
4
-based ferrites were synthesized by the solution combustion technique. The morphological and structural features and elemental composition of these doped ferrites were characterized by scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy. The analysis revealed improved structural features for (Sm
3+
)-doped copper–iron oxide ferrites and the formation of a homogeneous composite structure. Doping of a rare earth metal (Sm
3+
) into the Cu–Fe–O ferrite significantly enhanced the room-temperature electrical conductivity of the doped ferrite in comparison to its pure counterpart. The energy band gap value of the higher-concentration sample was found to decrease significantly in comparison to the pure ferrite due to enhanced charge density across the grain boundaries. Further, it was observed that (Sm
3+
) doping led to improved optical, magnetic, and dielectric response of the doped ferrites which was dependent on the concentration of the dopant. The dielectric constant of these doped ferrites was found to be higher at lower frequencies and decreased dramatically with increased frequencies due to the greater dielectric dispersion as well as electron hopping in the higher-frequency region. The magnetic properties showed strong dependence on both the sintering temperature and concentrations of (Sm
3+
) doping. The optical bandgap decreased significantly with the increase in concentration of (Sm
3+
) doping. In light of the ease of synthesis, improved electrical conductivity, and dielectric, magnetic, and optical properties, these SCFO ferrites hold promise as a potential material for optoelectronic applications.
For the first time, innovative and remarkable humidity sensing properties of solvent combustion produced spinel cobalt chromite nanoparticles based microporous materials have been presented. These ...features were identified by solution combustion. To create a capacitive humidity sensor, microporous samples were initially created by sintering a green tape of cobalt chromite that had been manufactured via tape casting. To finish the process, the samples were sandwiched between two parallel silver electrodes. The newly developed sensors have good humidity sensing capabilities over a wide range of relative humidity (RH), from 11 to 97%, with a detectable gain of 3 pF/%RH. Because of the significant rise in dielectric constant, the sensing properties can be attributed to the dielectric polarisation of moisture molecules that are absorbed on the surface of the CoCr
2
O
4
material and then condensed in the surface pores. A variety of complicated tests have been performed in order to get a knowledge of its physicochemical properties. These investigations resulted in the sensor’s remarkable moisture detection abilities.
Ferrites are a very common commodity in the modern world due to their very strong magnetic permeability, high resistivity, modest permittivity, high saturation magnetization, low power losses, low ...coercivity, low remanence magnetization, and low power losses. These properties are mainly depending on chemical composition, synthesis method, and other parameter. Further based on these parameter material exhibits noticeable properties. Aiming on these points we have prepared 100% replacement at A site AB
2
O
4
materials with several dopant i.e. Co
2+
, Ni
2+
, Cu
2+
. All the samples were prepared by solution combustion method using glucose as fuel. This method is the only one method very less expensive compare to other synthesis methods. The MFe
2
O
4
(M=Co
2+
, Ni
2+
, Cu
2+
) samples were characterised by XRD and VSM to confirm phase, structure, crystallinity, and magnetic behaviour of the samples. XRD data reveals that crystallite size were found decreases with changing transition metal 100% replacement at A site. Magnetic behaviour was studied by using VSM and results reveals that samples were turns ferrimagnetic to ferromagnetic nature with changing substitution. As a result of sensing study, these samples could be used to develop sensing materials in the future. According to the hysteresis analysis, the desorption mechanism is less than the adsorption process. At room temperature, the humidity sensing material is extremely stable at higher concentrations of Co ferrites. The low sensing response ferrites, on the other hand, have a lot of potential for sensor applications, hence our results help for permanent magnet applications. Since samples exhibits highly porosity so that these samples very good candidates for humidity sensor applications.
Herein, we report the synthesis of novel nickel ferrite doped with yttrium nanocomposite (NiFe
2−
x
Y
x
O
4
represented as NFY) thin film with multifunctional features such as mechanical robustness ...and strain sensing properties for EMI shielding applications in broadband microwave frequencies. The thin films of NiFe
2−
x
Y
x
O
4
were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic methods. Inclusion of iron and yttrium nanoparticles (NPs) into nickel acts as an excellent conducting component and improves the dielectric and magnetic characteristics of the nanocomposite thin films. Due to enhanced dielectric and magnetic features,
x
= 0.1 nanocomposite film with thickness of 0.5 mm shows strong absorption-dominated EM shielding behaviour of shielding efficiency − 23 dB (which is equivalent to 99.77% of shielding efficiency) in the broadband microwave frequency range. Moreover, the nanocomposite films of NiFe
2−
x
Y
x
O
4
exhibit superior long-term stability of EMI shielding efficiency under applied strains. Apart from superior shielding performance, these NiFe
2−
x
Y
x
O
4
nanocomposite films exhibit outstanding strain sensing characteristics. Owing to the properties such as light weight, mechanical flexibility, improved EMI-SE and superior strain sensing properties, this ferrites-based nanocomposite film can be used in foldable and wearable modern electronic gadgets as smart covering jacket over the shield.
