Cd Substitution Research Articles

Decoupled atomic contribution boosted high thermoelectric performance in mixed cation spinel oxides ACo2O4

Decoupling the interdependence of various transport parameters in materials has been an intractable challenge in designing efficient thermoelectric materials. Using the first-principles density functional theory and the semi-classical Boltzmann transport theory, we demonstrate that the crucial criteria of obtaining suitable electronic and thermal transport have been achieved by utilizing the presence of mixed cations in spinel oxides. Differently coordinated cations present in spinel oxides lead to decoupled cationic contribution to the electronic and thermal transport properties. While electronic transport properties are controlled by tetrahedrally coordinated cation B (Co), the octahedrally coordinated cations A (Zn/Cd) only contribute to the thermal transport of the system. The combination of heavy bands in the electronic dispersions and tetrahedrally coordinated environment of Co results into an enhanced power factor. Additionally, the substitution of Cd leads to one order of magnitude reduction in the lattice thermal conductivity (κl) without affecting the electronic transport properties. The significant reduction in κl has been attributed to the large mass difference, and remarkably strong anharmonic phonon scattering introduced by Cd. Simultaneously achieved high power factor and low lattice thermal conductivity result in a maximum figure of merit of 1.68 in CdCo2O4 spinel oxide. The approach of decoupling atomic contributions utilizing various cationic sites demonstrates a potential route to enhance thermoelectric performance.

High-Performance Ligand-Protected Metal Nanocluster Catalysts for CO2 Conversion through the Exposure of Undercoordinated Sites

Previous experimental breakthroughs reveal the potential to create novel heterogeneous catalysts for the electroreduction of CO2 to a high-value product CO using ligand-protected Au-based nanoclusters. Since the chemical composition and geometric structures have been precisely defined, it is possible to adopt robust design guidelines for the development of practical catalysts and to fundamentally elucidate the underlying reaction mechanism. In this short review, the computational progress made to understand the experimentally observed reduction process on the following subset of materials—Au25(SR)18−, Au24Pd(SR)18, Au23(SR)16− and Au21Cd2(SR)16−—is described. A significant finding from our first-principles mechanistic studies is that CO2 conversion on the fully ligand protected nanoclusters is thermodynamically unfavorable due to the very weak binding of intermediates on the surface region. However, the reaction becomes feasible when either Au or S sites are exposed through the removal of a ligand. The results particularly point to the role of undercoordinated S sites in the creation of highly functional heterogeneous catalysts that are both active and selective for the CO2 conversion process. The incorporation of dopants could significantly influence the catalytic reactivity of the nanoclusters. As demonstrated in the case of the monopalladium substitution in Au25(SR)18−, the presence of the foreign atom leads to an enhancement of CO production selectivity due to the greater stabilization of the intermediates. With the Cd substitution doping of Au23(SR)16−, the improvement in performance is also attributed to the enhanced binding strength of the intermediates on the geometrically modified surface of the nanocluster.

Introduced oxygen vacancies in cadmium ferrite anode materials via Zn2+ incorporation for high performance lithium-ion batteries

Cationic substitution strategy was recognized as an effective approach to create a defective structure and increase the oxygen vacancies in the crystal structure for improving the electrochemical performance of Li-ion batteries components. In this study, ZnxCd1-xFe2O4 nanoparticles were synthesized via a facile inexpensive process at low temperature. The collected XRD data confirmed the formation of cubic structure with Fd3m space group. HR-TEM investigations showed the size enlargement of spherical-like crystals with increasing the concentration of doping Zn2+ ion. FESEM and BET measurements indicated the conversion of micropores in pure CdFe2O4 into mesopores and macropores in Zn-doped CdFe2O4 samples. XPS results of O1s spectra elucidated that Zn-doped CdFe2O4 samples have higher conductivity due to the created lattice defects and oxygen species. Zn-doped CdFe2O4 anodes exhibit great improvement in their initial discharge capacities ∼1618 and 1880 mAhg−1 upon substitution of Cd with 5% and 10% Zn, respectively. Furthermore, 10% Zn-doped CdFe2O4 anode displayed the highest Li-ions diffusion coefficient and exchange current density due to the enhanced Li+ ions mobility. The increase in zinc content (0.0–0.1) led to a decrease in the DC activation energy from 0.11 to 0.09 eV.

Cd-substituted NiZnCo ferrite with high dielectric constant and low coercivity for high-frequency electronic devices

This work investigated the effect of replacing Zn 2+ ions with Cd 2+ ions on the microstructure and electromagnetic properties of NiZnCo ferrites. The studies show that the Cd 2+ ions substituted for Zn 2+ ions at the A sites (tetrahedral sites) of the ferrite lattice. The large ionic radius of the Cd 2+ ions can cause lattice distortion. Concurrently, the low melting point of CdO can effectively reduce the sintering temperature of NiZnCo ferrite, thereby significantly changing the magnetoelectric properties of NiZnCo ferrite. These changes are mainly manifested as the decrease in the saturation magnetization ( M s) from 66.6 to 58.5 emu/g and the increase in coercivity ( H c) from 31.2 to 34.8 Oe. The dielectric constant increases considerably, dielectric loss tanδ gradually decreases from 4.71 to 0.83 at 10 kHz, and DC resistivity ρ decreases considerably from 8.0 × 10 4 to 1.61 × 10 4 Ω m. Therefore, the substitution of Cd 2+ ions in NiZnCo ferrite provides excellent electrical and magnetic properties, which provide a reference for the development of high-frequency miniaturized electronic equipment.

Cadmium Substitution Effect on Microstructure and Magnetic Properties of Mg-Cu-Zn Ferrites

The microstructure, optical, and magnetic properties of CdxMg0.3-xCu0.2Zn0.5Fe2O4 ferrites prepared by the citrate auto-combustion method were investigated. The samples were analyzed by X-ray diffraction, scanning electron microscopy, UV-Vis spectroscopy, https://soh.iums.ac.ir/uploads/uv-vis_-_2.pptx X-ray energy-dispersive spectroscopy, Fourier-transform infrared spectroscopy, and vibrating sample magnetometer. Rietveld refinement of XRD patterns shows a single-phase cubic structure (space group Fd3¯m) for the samples with x up to 0.20, while the impurity phase of CdO is observed in the samples with x = 0.25, 0.30. As the substitution content increases, the presence of non-magnetic Cd2+ ions in the octahedral site and the migration of Fe3+ions from the octahedral site to the tetrahedral site decreases the saturation magnetization of the samples. Comparison of the bandgap energy of the samples shows an increasing trend with Cd substitution for x up to 0.20 and then decreases, which can be interpreted in terms of changes in the electronic structure of the samples. Improvement in dielectric properties of the samples with increase of Cd2+ content for x up to 0.20 may be attributed to easier transfer and electron exchange between Fe3+and M2+ ions.

Metal regulated organic–inorganic hybrid ferroelastic materials: [(CH3)3CN(CH3)2CH2F]2[MBr4] (M = Cd and Zn)

Two organic–inorganic hybrid compounds [(CH3)3CN(CH3)2CH2F]2[MBr4] (M = Cd and Zn) undergo ferroelastic phase transitions. The substitution of metal center Cd with Zn of inorganic anions regulate the ferroelastic phase transitions.

Sequential enhancement of proton conductivity by aliovalent cadmium substitution and post-synthetic esterolysis in a carboxylate-functionalized indium framework with dimethylaminium templates

A sequential improving strategy of aliovalent Cd(ii) substitution and post-synthetic ligand esterolysis has been proposed and implemented on a In(iii)-MOF. The modified framework Cd-BQ-COOH exhibits 300-fold enhanced value of proton conductivitiy.

Half-metallicity in smallest cage-like cluster of CdTe with doping of transition metal atoms

We report first principles theory based electronic structure studies of a semiconducting stoichiometric cage-like Cd9Te9 cluster. Substantial changes are observed in the electronic structure of the cluster on passivation with fictitious hydrogen atoms, in particular, widening of the energy gap between highest occupied molecular orbital and lowest unoccupied molecular orbital and enhancement in stability of cluster is seen. The cluster, when substitutionally mono-doped for a Cd by a set of 3d and 4d transition metal atoms (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Rh and Pd), is found to acquire polarization as seen from spin resolved density of states near Fermi level. Further, such mono-doping in passivated cluster shows half-metallic behavior. Mapping of partial density of states of each system on that of undoped cluster reveals additional levels caused by doping each TM atom separately. In the 3d elemental doping, Ti and Mn doping result into electron type doping whereas all other cases result into hole doped systems. For all the 4d elements studied, it is akin to the doping with holes for Cd substitution in the outer ring, whereas for Ru and Rh, there is electron type doping in case of substitution for Cd in central ring upon passivation. A comparison of partial density of states plots for bare and passivated clusters, on doping with transition metal atoms, suggests suitability of the cage-like cluster for spintronics applications.

Effect of Ga and Cd substitutions on the first-order antiferromagnetic transition in NdCo2Zn20

The cubic neodymium-based compound ${\mathrm{NdCo}}_{2}{\mathrm{Zn}}_{20}$ exhibits a first-order antiferromagnetic (AFM) transition at ${T}_{\text{N}}=0.53$ K. Strong magnetic fluctuations at temperatures up to 5 K were suggested by the downward curvature of the electrical resistivity $\ensuremath{\rho}(T)$ and the reduced magnetic entropy ${S}_{\text{m}}$ of $0.5R\mathrm{ln}2$ at ${T}_{\text{N}}$. In this study, we measured $\ensuremath{\rho}(T)$, the isothermal magnetization $M(B)$, magnetic susceptibility $\ensuremath{\chi}(T)$, and specific heat $C(T)$ of ${\mathrm{NdCo}}_{2}{\mathrm{Zn}}_{20\ensuremath{-}x}{\mathrm{Cd}}_{x}$ for $x=1$ and ${\mathrm{NdCo}}_{2}{\mathrm{Zn}}_{20\ensuremath{-}y}{\mathrm{Ga}}_{y}$ for $y=1$ and 2. The sharp peak of the magnetic specific heat ${C}_{\text{m}}(T)$ at ${T}_{\text{N}}$ for $x$ = 0 is changed to a weak and broad maximum at 0.55 K for $x$ = 1. This drastic change in ${C}_{\text{m}}(T)$ suggests that the isovalent Cd substitution for Zn disorders the exchange interactions between the Nd moments to hinder the first-order AFM transition. On the other hand, ${C}_{\text{m}}(T)$ for $y=1$ and 2 exhibits a lambda-shaped anomaly, which is a characteristic of a second-order AFM transition, at elevated temperatures of 0.78 and 1.5 K, respectively. The stabilization of the AFM order by the Ga substitution indicates that $4p$ electron doping strengthens the AFM interaction. We therefore propose that the first-order transition in ${\mathrm{NdCo}}_{2}{\mathrm{Zn}}_{20}$ is maintained by competitive magnetic interactions inherent in the Nd diamond sublattice.

Fatigue Analysis of Threaded Components with Cd and Zn-Ni Anticorrosive Coatings

The influence of the electrodeposition of cadmium and zinc-nickel and the stress concentration effect on the fatigue behavior of AISI 4140 steel threaded components were studied. Axial fatigue tests at room temperature with a stress ratio of R = 0.1 were performed using standard and threaded specimens with and without nut interface under base material, cadmium, and zinc-nickel-coated conditions. Finite element analysis (FEA) was used, considering both elastic and elastoplastic models, to quantify the stress distribution and strain for threaded specimens with and without a nut interface. The numeric results were correlated to the experimental fatigue data of threaded components with and without the nut interface, to allow the oil & gas companies to extrapolate the results for different thread dimensions, since the experimental tests are not feasible to be performed for all thread interfaces. Scanning electron microscopy (SEM) was used to analyze the fracture surfaces. The stress concentration factor had a greater influence on the fatigue performance of threaded components than the effect of the Cd and Zn-Ni coatings. The fatigue life of studs reduced by about 58% with the nut/stud interface, compared to threaded components without nuts. The elastoplastic FEA results showed that studs with a stud/nut interface had higher stress values than the threaded specimens without a nut interface. The FEA results showed that the cracks nucleated at the regions with higher strain, absorbed energy, and stress concentration. The substitution of Cd for a Zn-Ni coating was feasible regarding the fatigue strength for threaded and smooth components.

Thermostructural and Elastic Properties of PbTe and Pb0.884Cd0.116Te: A Combined Low-Temperature and High-Pressure X-ray Diffraction Study of Cd-Substitution Effects

Rocksalt-type (Pb,Cd)Te belongs to IV–VI semiconductors exhibiting thermoelectric properties. With the aim of understanding of the influence of Cd substitution in PbTe on thermostructural and elastic properties, we studied PbTe and Pb0.884Cd0.116Te (i) at low temperatures (15 to 300 K) and (ii) at high pressures within the stability range of NaCl-type PbTe (up to 4.5 GPa). For crystal structure studies, powder and single crystal X-ray diffraction methods were used. Modeling of the data included the second-order Grüneisen approximation of the unit-cell-volume variation, V(T), the Debye expression describing the mean square atomic displacements (MSDs), <u2>(T), and Birch–Murnaghan equation of state (BMEOS). The fitting of the temperature-dependent diffraction data provided model variations of lattice parameter, the thermal expansion coefficient, and MSDs with temperature. A comparison of the MSD runs simulated for the PbTe and mixed (Pb,Cd)Te crystal leads to the confirmation of recent findings that the cation displacements are little affected by Cd substitution at the Pb site; whereas the Te displacements are markedly higher for the mixed crystal. Moreover, information about static disorder caused by Cd substitution is obtained. The calculations provided two independent ways to determine the values of the overall Debye temperature, θD. The resulting values differ only marginally, by no more than 1 K for PbTe and 7 K for Pb0.884Cd0.116Te crystals. The θD values for the cationic and anionic sublattices were determined. The Grüneisen parameter is found to be nearly independent of temperature. The variations of unit-cell size with rising pressure (the NaCl structure of Pb0.884Cd0.116Te sample was conserved), modeled with the BMEOS, provided the dependencies of the bulk modulus, K, on pressure for both crystals. The K0 value is 45.6(2.5) GPa for PbTe, whereas that for Pb0.884Cd0.116Te is significantly reduced, 33.5(2.8) GPa, showing that the lattice with fractional Cd substitution is less stiff than that of pure PbTe. The obtained experimental values of θD and K0 for Pb0.884Cd0.116Te are in line with the trends described in recently reported theoretical study for (Pb,Cd)Te mixed crystals.

Mere Anarchy is Loosed: Structural Disorder in Cu2Zn1–xCdxSnS4

Substitution of Cd into the photovoltaic material Cu2ZnSnS4 has been previously shown to improve power conversion efficiencies, and although various models for the structural disorder have been proposed, full characterization of Cu2Zn1–xCdxSnS4 has been hampered by a lack of understanding about the local structure around individual atoms. Through a combination of powder X-ray diffraction and solid-state NMR spectroscopy (119Sn, 113Cd, 63Cu, and 67Zn), the detailed structures of the entire series Cu2Zn1–xCdxSnS4 (x = 0–1), prepared as bulk samples by reaction of the elements at 800 °C, have been examined. The ordered kesterite structure in space group I4̅ of the end-member Cu2ZnSnS4 (x = 0) was retained up to Cu2Zn0.7Cd0.3SnS4 (x = 0.3) and the stannite structure in space group I4̅2m from Cu2Zn0.6Cd0.4SnS4 (x = 0.4) to the end-member Cu2CdSnS4 (x = 1). Although the structural transition at x = 0.4 was confirmed, 113Cd NMR spectroscopy reveals the coexistence of phases with I4̅ and I4̅2m structures in the intermediate region (x = 0.3–0.4), evidence for which was previously unattainable from XRD data alone. The 119Sn NMR spectra indicated the presence of Sn sites surrounded within distinct local chemical environments imparted by the distribution of Zn and Cd atoms disordered within the second coordination sphere, which could be resolved by their isotropic chemical shifts and quantified by their peak areas. Ultrahigh-field (21.1 T) 63Cu NMR spectroscopy revealed the two sets of Cu sites in the I4̅ structure expected for the lightly Cd-substituted members (up to Cu2Zn0.8Cd0.2SnS4) and one set of Cu sites in the I4̅2m structure for the more heavily substituted members. The balance of evidence from the comparison of experimental and DFT-computed 63Cu and 67Zn NMR spectra suggests that Cu/Zn disorder does not occur. Instead, Cd substitution in Cu2Zn1–xCdxSnS4 proceeds exclusively through disorder of Zn and Cd atoms, at least in the bulk samples examined.

Comment on “Unconventional enhancement of ferromagnetic interactions in Cd-doped GdFe2Zn20 single crystals studied by ESR and Fe57 Mössbauer spectroscopies”

In the recent publication, Phys. Rev. B 102, 144420 (2020), Cabrera-Baez et al. present a study of the effects of Cd-substitution for Zn in the ferromagnetic compound GdFe2Zn20. As part of this paper, they claim that for GdFe2Zn18.6Cd1.4 the effective moment of Gd is reduced by 25% and the saturated moment of Gd is reduced by over 40%. We regrew representative members of the GdFe2Zn(20-x)Cdx series and did not find any such reductions. In addition, we measured several crystals from the growth batch that was used by Cabrera-Baez et al. and did not see such reductions. Although there is a modest increase in TC with Cd substitution, there is no significant change in the Gd effective moment or the saturated moment associated with the low temperature ferromagnetic state.

Crystal, local atomic, and local electronic structures of YbFe2Zn20−xCdx(0≤x≤1.4) : A multiband system with possible coexistence of light and heavy fermions

The partial (up to 7 %) substitution of Cd for Zn in the Yb-based heavy-fermion material YbFe$_2$Zn$_{20}$ is known to induce a slight ($\sim 20$ %) reduction of the Sommerfeld specific heat coefficient $\gamma$ and a huge (up to two orders of magnitude) reduction of the $T^2$ resistivity coefficient $A$, corresponding to a drastic and unexpected reduction of the Kadowaki-Woods ratio $A/\gamma ^2$. Here, Yb $L_{3}$-edge X-ray absorption spectroscopy shows that the Yb valence state is close to $3+$ for all $x$, whereas X-ray diffraction reveals that Cd replace the Zn ions only at the $16c$ site of the $Fd\bar{3}m$ cubic structure, leaving the $48f$ and $96g$ sites with full Zn occupation. Ab-initio electronic structure calculations in pure and Cd-doped materials, carried out without considering correlations, show multiple conduction bands with only minor modifications of the band dispersions near the Fermi level and therefore do not explain the resistivity drop introduced by Cd substitution. We propose that the site-selective Cd substitution introduces light conduction bands with substantial contribution of Cd($16c$) $5p$ levels that have weak coupling to the Yb$^{3+}$ $4f$ moments. These light fermions coexist with heavy fermions originated from other conduction bands with larger participation of Zn($48f$ and $96g$) $4p$ levels that remain strongly coupled with the Yb$^{3+}$ local moments.

Ultralow Thermal Conductivity and Enhanced Figure of Merit for CuSbSe2 via Cd-Doping

Thermoelectric properties of CuSb1–xCdxSe2 (x = 0–0.08) compounds, prepared by vacuum melting, were studied at temperatures of 300–675 K. The results indicate that Cd doping causes both remarkable increase in the Seebeck coefficient and drastic drop of lattice thermal conductivity. The enhancement of thermopower originates mainly from increase of electronic density of states, while the drop of lattice thermal conductivity can be ascribed to enhanced phonon scattering by introduced impurity (dopant) atoms. As a consequence, thermoelectric figure of merit ZT is improved with a maximum ZT = 0.55 (at 675 K) being reached for CuSb0.98Cd0.02Se2, which is around 2.2-fold higher than that of the CuSbSe2 pristine compound. Our results indicate that Cd substitution is a feasible way to improve thermoelectric performance of the CuSbSe2-based system.

Chemical speciation in Gd−Cd−M (M=Zn, Au) quasicrystal approximants

AbstractWe investigated the effect of partial replacement of Cd by M=Au and Zn in the crystal structure of the 1/1 Tsai‐type quasicrystal approximant (AC) GdCd6. Compositionally homogeneous single crystal samples Gd(Cd0.87Zn0.13(1))6 and Gd(Cd0.80Au0.20(1))6 were grown from melts Gd5(Cd0.8Zn0.2)100 and Gd1(Cd0.9Au0.1)100, respectively, and isolated by centrifugation. The M for Cd substitution in GdCd6 is accompanied with a sizeable reduction of the cubic unit cell parameter, from 15.514(2) Å to 15.329(1) Å (Zn) and 15.314(1) Å (Au). Site preferences were established from single crystal X‐ray diffraction data. A clear preference of atomic sites for Au and Zn is noted which is compared to earlier reported Yb(Cd0.75Mg0.25)6. Three and two out of in total seven crystallographic sites defining the Cd partial structure accept preferably metals more and less electronegative than Cd, respectively, and are classified as negatively and positively polarized sites in the binary 1/1 AC.

Unconventional enhancement of ferromagnetic interactions in Cd-doped GdFe2Zn20 single crystals studied by ESR and Fe57 Mössbauer spectroscopies

Single crystals of $\mathrm{Gd}{\mathrm{Fe}}_{2}{\mathrm{Zn}}_{20\ensuremath{-}x}{\mathrm{Cd}}_{x}$ ($0.0l\phantom{\rule{4pt}{0ex}}x\phantom{\rule{4pt}{0ex}}l1.4$) were grown and characterized through structural, magnetic, and electronic properties using x-ray diffraction, field- and temperature-dependent magnetization, specific heat, $^{57}\mathrm{Fe}$ M\ossbauer spectroscopy, and electron spin resonance (ESR). A negative chemical pressure effect is accompanied by an unexpected increase of ${T}_{C}$ from 86 to 96 K, together with a reduction of the magnetic effective moment and saturation magnetic moment, as evidenced by all of the experimental techniques. From the microscopic point of view, probing at the $4f$ electron level and the Fe nucleus has allowed the extraction of important information about the configuration and the effective role of the partial Cd substitution for Zn in this ferromagnetic system. Our $^{57}\mathrm{Fe}$ M\ossbauer spectroscopy experiments show a negligible variation of the hyperfine field at the Fe site, and ESR experiments reveal an enhancement of the Korringa-type relaxation and a molecular field effect as Cd is incorporated. This complex behavior is assigned to a possible reconstruction of the Fermi surface and/or a new distribution of the $d$ type of conduction electrons in response to the negative chemical pressure, leading to an enhancement of the ferromagnetic transition temperature in a generalized Ruderman-Kittel-Kasuya-Yosida interaction scenario.

Structural-transition-driven antiferromagnetic to spin-glass transition in Cd–Mg–Tb 1/1 approximants

The magnetic susceptibility of the 1/1 approximants to icosahedral quasicrystals in a series of Cd85−xMgxTb15 (x = 5, 10, 15, 20) alloys was investigated in detail. The occurrence of antiferromagnetic (AFM) to spin-glass (SG)-like transition was noticed by increasing Mg. Transmission electron microscopy analysis evidenced a correlation between the magnetic transition and suppression of the monoclinic superlattice ordering with respect to the orientation of the Cd4 tetrahedron at T > 100 K. The possible origins of this phenomenon were discussed in detail. The occurrence of the AFM to SG-like magnetic transition is associated with the combination of chemical disorder due to a randomized substitution of Cd with Mg and the orientational disorder of the Cd4 tetrahedra.

Analysis of fluctuation conductivity in Y1−хCdxBa2Cu3O7−δ (x = 0−0.4)

The effect that the partial substitution of Cd for Y has on the mechanism of excess conductivity formation in polycrystalline Y1−хCdxBa2Cu3O7−δ with x = 0 (Y1), 0.1 (Y2), 0.3 (Y3), and 0.4 (Y4) is investigated. The resistivity ρ of the samples increases markedly with increasing x, and the critical temperature of the superconducting (SC) state transition, Tc, decreases. The mechanism responsible for the formation of fluctuation conductivity, σ'(T), is considered within the framework of the Aslamazov–Larkin theory near Tc. The Ginzburg temperature (TG), the critical temperature in the mean-field approximation (Tcmf), the temperature of the 3D–2D crossover (T0), and T01, which limits the region of the SC fluctuations from above, are determined. It is shown that doping with Cd at x = 0−0.4 increases the coherence length along the c axis, ξc(0), by 2.7 times, and the distance between the CuO2 planes, d01, by 2.2 times. The temperature dependences of the pseudogap (PG), Δ*(T), are determined by analyzing the excess conductivity within the framework of the local pair model. It is found that with an increase in substitution, the maximum value of the PG Δ*(Tpair) decreases from 250.2 to 215.7 K, while the real value of the PG, measured at TG,Δ*(TG), increases from 217.4 to 224.2 K.

Synthesis and characterization of electrospun Ni[formula omitted]Co[formula omitted]Cd[formula omitted]Nd[formula omitted]Fe[formula omitted]O4 nanofibers

We report here the production of novel Ni0.5Co0.5−xCdxNd0.02Fe1.78O4 nanofibers (NFs) (0.00 ≤ x ≤ 0.25) via electrospinning method with using polyvinylpyrrolidone (PVP) as a polymer agent. The investigation of the partial substitution effect of Co by Cd ions in Co0.5Ni0.5Fe1.78Nd0.02O4 NFs on their morphological, structural and magnetic properties was performed. The XRD confirmed the successful formation of Ni0.5Co0.5−xCdxNd0.02Fe1.78O4 (0.00 ≤ x ≤ 0.25) NFs with cubic structure. The hyperfine parameters were determined from the analysis of Mössbauer results. The hyperfine magnetic field of both sites was not much affected by the substitution. Mössbauer analysis indicated that the Cd2+ ions strongly occupy A site and the Fe3+ions emigrated from A site to B site, and hence the content of Co2+ions diminished at B site. Room temperature (RT; T = 300K) and 10 K magnetization curves were investigated via vibrating sample magnetometer (VSM). All prepared samples displayed ferrimagnetic behavior at both measured temperatures. The saturation magnetization (Ms) enhances from x = 0.00 to 0.05 and thereafter reduces with the further increase in Cd2+ ion contents. All the Cd-substituted samples displayed higher Ms values than that of the non-substituted sample. The improvement in Ms values with Cd substitution is largely ascribed to the surface spins effects and cations distribution on Td and Oh sites. Magnetic moments, remanence (Mr) and coercivity (Hc) were determined and investigated.