The Effect of Al3+ Ions Concentration on DC Conductivity and Curie Temperature of Ni - Spinel Ferrite

A series of Al substituted Ni spinel ferrites with the empirical formula , where x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5, were prepared by conventional ceramic double sintering method. DC electric properties and initial permeability ( ) were carried out for the prepared series of samples from room temperature to well beyond the Curie point temperature ( ). The thermal behavior of the DC electric conductivity for the prepared samples indicated that they act as semiconducting materials. On the other hand, DC electric conductivity is greatly affected when the  ions are increased. The DC electrical conductivity results were interpreted in terms of electron hopping model. The calculated activation energy in the ferrimagnetic region was less than that in paramagnetic region. The initial permeability showed constant values from room temperature to , then it decreased sharply. The Curie temperature was determined from DC electrical properties and initial permeability. was found to decrease with increasing of  ions

Curie Points and Direct Current Electrical Conductivity for Inverse Li-Spinel Ferrite Replaced by Zn2+ Ion

The conventional ceramic double sintering method was used to prepare a series of mixed Li-Zn spinel ferrites (SFs) Direct electric (DC) electrical conductivity (σ) and inductance (L) were studied for the prepared series of samples from room temperature to well beyond the Curie point (TC). σ was measured as a function of temperature, the relation between lnσ with 1/T indicated that σ was increased with increasing of the temperature, which proves that the prepared samples have a semiconductor behavior. The maximum value of the σ was reported for the sample of x = 0.8. The σ results were interpreted in terms of hopping model. The relation between lnσT and 1/T showed a change in the slope which is attributed to the change of samples from ferrimagnetic to paramagnetic at TC. The values of L increased exponentially from room temperature up to TC, and then they decreased sharply. The calculated activation energy Ea in the ferromagnetic region was less than that in paramagnetic region. The calculated activation energy (Ea) decreased with increasing of Zn content. The values of the TC for the prepared samples were determined from σ and L measurements, which decreased with increasing of Zn content.The conventional ceramic double sintering method was used to prepare a series of mixed Li-Zn spinel ferrites (SFs) Direct electric (DC) electrical conductivity (σ) and inductance (L) were studied for the prepared series of samples from room temperature to well beyond the Curie point (TC). σ was measured as a function of temperature, the relation between lnσ with 1/T indicated that σ was increased with increasing of the temperature, which proves that the prepared samples have a semiconductor behavior. The maximum value of the σ was reported for the sample of x = 0.8. The σ results were interpreted in terms of hopping model. The relation between lnσT and 1/T showed a change in the slope which is attributed to the change of samples from ferrimagnetic to paramagnetic at TC. The values of L increased exponentially from room temperature up to TC, and then they decreased sharply. The calculated activation energy Ea in the ferromagnetic region was less than that in paramagnetic region. The calculated activation energy (Ea) decreased with increasing of Zn content. The values of the TC for the prepared samples were determined from σ and L measurements, which decreased with increasing of Zn content

AC Conductivity and Dielectric Properties of Cu–Zn ferrites

In this work, we have studied the effects of the 2 Zn ions on the electric and the dielectric properties of the Cu spinel ferrite. The mixed Cu-Zn spinel ferrite, of chemical formula 1 s s 2 4 Cu Zn Fe O , where s stepped by 0.2 according to ( 0.0 s 1.0), were prepared from purity metal oxides using the standard ceramic preparation. The AC conductivity was determined for the ferrite samples in the applied frequency range (10 10 )Hz 4 6 . In this range of frequency, the AC conductivity increases rapidly as a function of the applied frequency. The dielectric properties for the ferrite samples were also determined at room temperature. The general trend for all samples was found to decrease continuously with increasing of the applied frequency. The measurements of the electric and the dielectric properties show that, the behavior of the ferrite samples is similar to that of the semiconductor materials. The results of the electric and dielectric properties are inadequate to previous studies for various ferrite compounds. The electric conductivity for the samples was explained using the electron hopping model.In this work, we have studied the effects of the 2 Zn ions on the electric and the dielectric properties of the Cu spinel ferrite. The mixed Cu-Zn spinel ferrite, of chemical formula 1 s s 2 4 Cu Zn Fe O , where s stepped by 0.2 according to ( 0.0 s 1.0), were prepared from purity metal oxides using the standard ceramic preparation. The AC conductivity was determined for the ferrite samples in the applied frequency range (10 10 )Hz 4 6 . In this range of frequency, the AC conductivity increases rapidly as a function of the applied frequency. The dielectric properties for the ferrite samples were also determined at room temperature. The general trend for all samples was found to decrease continuously with increasing of the applied frequency. The measurements of the electric and the dielectric properties show that, the behavior of the ferrite samples is similar to that of the semiconductor materials. The results of the electric and dielectric properties are inadequate to previous studies for various ferrite compounds. The electric conductivity for the samples was explained using the electron hopping model

Synthetize and Magnetic Properties of Ni Substituted Polycrystalline Zn-spinel Ferrites

The mixed polycrystalline Ni1-sZnsFe2O4 ferrites where s is the percentage increments of Zn ions, were prepared using the standard double sintering by mixing pure metal oxides NiO, ZnO and Fe2O3. The netmagnetization (Mnet)was studied at room temperature as a function of applied magnetic field(H)over the range of (0-45) Oe ina constant magnetizing frequency (ν = 50 Hz). Mnet show increasing with increasing of H. Mnet is found to increase for the samples of s= 0.0, 0.2, 0.4 and 0.6 then decreases there after while the concentration of Zn increases in matrix i.e. samples of s = 0.8 and 1.0. The increasing of the magnetization with increasing of Zn+2 ions for the samples of s= 0.0, 0.2 and 0.4 explained by Neel’s two-sublattice model. However,for the decreasing of magnetization beyond > 0.6 explained by Yafet and Kittel for the three-sublattice model. The Yafet-Kittel angle (YK) for the samples of s = 0.4 to s = 1.0, shows increasing with increasing of the amount of nonmagnetic ions Zn+2 in ferrite. The relation between H and relative permeability (µr) show an interesting behavior of the present ferrite samples. µr for the samples of s = 0.0, 0.2, 0.8 and 1.0 is found to be smaller than the samples with s= 0.4 and s= 0.6. Substitution of the non-magnetic Zn+2 ions in Ni spinel ferrite has a tremendous influence such the magnetic properties. Furthermore, Zn content has significant influence on the magnetic properties for Ni ferrites, so, the mixed Ni-Zn spinel ferrite is considered a soft ferrite material, which is proved an interesting material for technological and scientific applications.The mixed polycrystalline Ni1-sZnsFe2O4 ferrites where s is the percentage increments of Zn ions, were prepared using the standard double sintering by mixing pure metal oxides NiO, ZnO and Fe2O3. The netmagnetization (Mnet)was studied at room temperature as a function of applied magnetic field(H)over the range of (0-45) Oe ina constant magnetizing frequency (ν = 50 Hz). Mnet show increasing with increasing of H. Mnet is found to increase for the samples of s= 0.0, 0.2, 0.4 and 0.6 then decreases there after while the concentration of Zn increases in matrix i.e. samples of s = 0.8 and 1.0. The increasing of the magnetization with increasing of Zn+2 ions for the samples of s= 0.0, 0.2 and 0.4 explained by Neel’s two-sublattice model. However,for the decreasing of magnetization beyond > 0.6 explained by Yafet and Kittel for the three-sublattice model. The Yafet-Kittel angle (YK) for the samples of s = 0.4 to s = 1.0, shows increasing with increasing of the amount of nonmagnetic ions Zn+2 in ferrite. The relation between H and relative permeability (µr) show an interesting behavior of the present ferrite samples. µr for the samples of s = 0.0, 0.2, 0.8 and 1.0 is found to be smaller than the samples with s= 0.4 and s= 0.6. Substitution of the non-magnetic Zn+2 ions in Ni spinel ferrite has a tremendous influence such the magnetic properties. Furthermore, Zn content has significant influence on the magnetic properties for Ni ferrites, so, the mixed Ni-Zn spinel ferrite is considered a soft ferrite material, which is proved an interesting material for technological and scientific applications

Investigation of the Effect of Zn Ions Concentration on DC Conductivity and Curie Temperature of Ni-spinel Ferrite

The mixed polycrystalline ferrites Ni1-sZnsFe2O4, were obtained using the standard double sintering technique by mixing high purity of metal oxides NiO, ZnO and Fe2O3 for different concentration of Zn ion. DC electric properties and inductance of the prepared samples were carried out over the temperature range of 300 up to 773 K using two probe method and LCR meter. The thermal dependence of DC electrical conductivity (σDC) for the mixed Ni-Zn spinel ferrites with different Zn concentrations was investigated. In general, σDC found to be increased with both increasing temperature and Zn content. The thermal measurement of σDC confirmed the semiconductor behavior for Zn substituted Ni spinel ferrites and follows Arrhenius relation in the investigated temperature region. The variation of σDC indicated that the conduction mechanism was correlated to a small polaron-hopping. The activation energies of both regions, ferrimagnetic (Ef) and paramagnetic (Ep) and △E=Ep-Ef for all studied compositions were estimated. The calculated activation energy in the ferrimagnetic region was found to be less than that in paramagnetic region. The influenced of increased Zn ions on σDCand activation energies was investigated. From these results, it is found that △E and σDC decrease with increasing of Zn content. The inductance measurements for the prepared samples show constant values at low temperature range up to Curie temperature (TC), then the inductance decrease sharply except for ZnFe2O4 which confirmed that it is a paramagnetic at room temperature. The Curie temperature was determined from σDC and inductance measurement, which was found to be nearly the same and they decreased with increasing of Zn ions. The experimental results reveal that the electric properties and inductance, which can be dramatically changed by substitution of the non-magnetic Zn ions in Ni spinel ferrite. These improved properties of the mixed Ni-Zn spinel ferrite suggest uses as a soft ferrite material, which is proved an interest material for technological and scientific applications.The mixed polycrystalline ferrites Ni1-sZnsFe2O4, were obtained using the standard double sintering technique by mixing high purity of metal oxides NiO, ZnO and Fe2O3 for different concentration of Zn ion. DC electric properties and inductance of the prepared samples were carried out over the temperature range of 300 up to 773 K using two probe method and LCR meter. The thermal dependence of DC electrical conductivity (σDC) for the mixed Ni-Zn spinel ferrites with different Zn concentrations was investigated. In general, σDC found to be increased with both increasing temperature and Zn content. The thermal measurement of σDC confirmed the semiconductor behavior for Zn substituted Ni spinel ferrites and follows Arrhenius relation in the investigated temperature region. The variation of σDC indicated that the conduction mechanism was correlated to a small polaron-hopping. The activation energies of both regions, ferrimagnetic (Ef) and paramagnetic (Ep) and △E=Ep-Ef for all studied compositions were estimated. The calculated activation energy in the ferrimagnetic region was found to be less than that in paramagnetic region. The influenced of increased Zn ions on σDCand activation energies was investigated. From these results, it is found that △E and σDC decrease with increasing of Zn content. The inductance measurements for the prepared samples show constant values at low temperature range up to Curie temperature (TC), then the inductance decrease sharply except for ZnFe2O4 which confirmed that it is a paramagnetic at room temperature. The Curie temperature was determined from σDC and inductance measurement, which was found to be nearly the same and they decreased with increasing of Zn ions. The experimental results reveal that the electric properties and inductance, which can be dramatically changed by substitution of the non-magnetic Zn ions in Ni spinel ferrite. These improved properties of the mixed Ni-Zn spinel ferrite suggest uses as a soft ferrite material, which is proved an interest material for technological and scientific applications

FT-IR Studies of Nickel Substituted Polycrystalline Zinc Spinel Ferrites for Structural and Vibrational Investigations

FT-IR spectra of Ni1-sZnsFe2O4 spinel ferrite, s changed by 0.2 according to 0.0 s 1.0, have been analyzed in the frequency range (350−1000) cm-1. Six polycrystalline ferrites samples were synthesized using the conventional standard double sintering ceramic method. Two main absorption bands were observed, their positions were found to be strongly dependent on s-value. The high frequency band in the range 550-600 cm−1 and a low frequency band at around 400 cm−1 were assigned to tetrahedral Td and octahedral Oh sites, respectively, of spinel lattice. Force constant (FC) was calculated for Tdand Oh sites and was found to decrease with increasing Zn ions. Threshold frequency nth for the electronic transition was determined and found to increase with increasing Zn ions. Cations distribution for the prepared mixed ferrite was concluded based on the FT-IR spectra. The ionic radii for each site were correlated to the cations distribution of the given ferrite.FT-IR spectra of Ni1-sZnsFe2O4 spinel ferrite, s changed by 0.2 according to 0.0 s 1.0, have been analyzed in the frequency range (350−1000) cm-1. Six polycrystalline ferrites samples were synthesized using the conventional standard double sintering ceramic method. Two main absorption bands were observed, their positions were found to be strongly dependent on s-value. The high frequency band in the range 550-600 cm−1 and a low frequency band at around 400 cm−1 were assigned to tetrahedral Td and octahedral Oh sites, respectively, of spinel lattice. Force constant (FC) was calculated for Tdand Oh sites and was found to decrease with increasing Zn ions. Threshold frequency nth for the electronic transition was determined and found to increase with increasing Zn ions. Cations distribution for the prepared mixed ferrite was concluded based on the FT-IR spectra. The ionic radii for each site were correlated to the cations distribution of the given ferrite

A Structural Study of Cu-Zn Ferrites by Infrared Spectra

Infrared (IR) spectra of Zn2+ ions substituted Cu spinel ferrite, having the general formula Cu1-sZnsFe2O4, (where s stepped by 0.2 such that0.0s1.0), have been analyzed in the frequency range(200-1000)cm-1. The above mixed ferrites were prepared by the conventional standard double sintering ceramic method. Four absorption bands were observed, their position and intensity were found to be strongly dependent on s-value. Mainly, two prominent bands were observed, a high frequency band νT at around (536-568) cm-1 and a low frequency band νO at around (394) cm-1 were assigned to tetrahedral Td and octahedral Oh sites, respectively, of spinel lattice.Upon introducing Zn2+ions, IR spectra indicated new shoulders or splitting in the absorption bands, such the first primary band νT which consists of two shoulders at about (700 and 600)cm-1. A small absorption band ν3 was observed at about (300-325) cm-1. This may indicate the presence of the divalent metal ion-oxygen complex on Oh sites. Other small weak absorption band ν4 was, also, observed at about (265-270) cm-1. Its intensity increased with the addition of Zn2+ions. Force constant FC was calculated for Td and Oh sites, and was found to decrease with increasing Zn2+ ions. Half band widths of Td sites (ΓT) and Oh sites (ΓO) changed linearly with increasing Zn2+ ions. Threshold frequency νth for the electronic transition was determined and found to increase with increasing Zn2+ions. On the basis of the analysis of IR absorption bands, we concluded the cations distribution for the given mixed ferrite. The ionic radii for each site were correlated to the cations distribution of the given ferrite.Infrared (IR) spectra of Zn2+ ions substituted Cu spinel ferrite, having the general formula Cu1-sZnsFe2O4, (where s stepped by 0.2 such that0.0s1.0), have been analyzed in the frequency range(200-1000)cm-1. The above mixed ferrites were prepared by the conventional standard double sintering ceramic method. Four absorption bands were observed, their position and intensity were found to be strongly dependent on s-value. Mainly, two prominent bands were observed, a high frequency band νT at around (536-568) cm-1 and a low frequency band νO at around (394) cm-1 were assigned to tetrahedral Td and octahedral Oh sites, respectively, of spinel lattice.Upon introducing Zn2+ions, IR spectra indicated new shoulders or splitting in the absorption bands, such the first primary band νT which consists of two shoulders at about (700 and 600)cm-1. A small absorption band ν3 was observed at about (300-325) cm-1. This may indicate the presence of the divalent metal ion-oxygen complex on Oh sites. Other small weak absorption band ν4 was, also, observed at about (265-270) cm-1. Its intensity increased with the addition of Zn2+ions. Force constant FC was calculated for Td and Oh sites, and was found to decrease with increasing Zn2+ ions. Half band widths of Td sites (ΓT) and Oh sites (ΓO) changed linearly with increasing Zn2+ ions. Threshold frequency νth for the electronic transition was determined and found to increase with increasing Zn2+ions. On the basis of the analysis of IR absorption bands, we concluded the cations distribution for the given mixed ferrite. The ionic radii for each site were correlated to the cations distribution of the given ferrite

Synthesis and ac properties of mixed li-zn ferrites

The mixed polycrystalline ferrites 〖Li〗_0.5(1-x) 〖Zn〗_x 〖Fe〗_(2.5-0.5x) O_4 were prepared by the conventional solid state method using high purity metal oxides ZnO,〖Fe〗_2 O_3 and LiCO_3for different concentration of Zn2+ions. Double probe electrode method was used to study the AC properties: the AC electrical conductivity (σ), the dielectric constant: real(ε'), imaginary (ε'') and complex (ε*), and the dielectric loss tangent (tan δ) over therange of the appliedfrequency (f=1 KHz-5 MHz)at room temperature. σincreased exponentially with the increasing f where the maximum value was for the sample 〖Li〗_0.3 〖Zn〗_0.4 〖Fe〗_2.3 O_4. The obtained results of the dielectric parameter (ε', ε'', ε* andtan δ), also, decreased exponentially with increasing f, which confirmsthe normal spinel ferrite behavior. The behavior of AC propertiescan be elucidated on the basis of the exchanged electrons between . The obtained results reveal that the AC properties change by substitution of the Zn2+ionsin Li-spinel ferrite matrix.The mixed polycrystalline ferrites 〖Li〗_0.5(1-x) 〖Zn〗_x 〖Fe〗_(2.5-0.5x) O_4 were prepared by the conventional solid state method using high purity metal oxides ZnO,〖Fe〗_2 O_3 and LiCO_3for different concentration of Zn2+ions. Double probe electrode method was used to study the AC properties: the AC electrical conductivity (σ), the dielectric constant: real(ε'), imaginary (ε'') and complex (ε*), and the dielectric loss tangent (tan δ) over therange of the appliedfrequency (f=1 KHz-5 MHz)at room temperature. σincreased exponentially with the increasing f where the maximum value was for the sample 〖Li〗_0.3 〖Zn〗_0.4 〖Fe〗_2.3 O_4. The obtained results of the dielectric parameter (ε', ε'', ε* andtan δ), also, decreased exponentially with increasing f, which confirmsthe normal spinel ferrite behavior. The behavior of AC propertiescan be elucidated on the basis of the exchanged electrons between . The obtained results reveal that the AC properties change by substitution of the Zn2+ionsin Li-spinel ferrite matrix

False Beliefs About Diabetes Mellitus in the Kurdistan Region of Iraq: A Population-Based Study

Background. Diabetes mellitus (DM) is a chronic, non-transmissible health condition distinguished by high blood glucose levels caused by faulty insulin secretion and impaired insulin activity. People play an essential role in preventing and managing their illnesses. Thus, the misconceptions may negatively influence the prevention and management of DM. The aim of this study was to gauge the extent of knowledge among the general population concerning DM, to determine the prevalence of misconceptions about DM in the community, and to find the factors influencing them. Methods. A population-based study was conducted in Duhok Province, the Kurdistan Region of Iraq. A total of 2,305 adults were enrolled in the study. The study data were collected by face-to-face interview. The survey questionnaire comprised two sections: the first section included basic demographic characteristics of participants, while the second section consisted of ten questions to identify common misconceptions about DM among participants. Results. Among the participants, there were 1,406 (61.0%) females. Participants’ age ranged from 18 to 90 years (the mean age: 54 ± 13.69 years). The most common misconceptions positively responded to were “Will I become addicted to insulin if I start taking it?”, followed by“ Does DM occur because of increased sugar intake?”. Male gender was associated with higher level of misconceptions. In addition, the misconceptions were more prevalent among diabetics as they might seek treatment from non-professionals. There was a significant association between education status and the prevalence of misconceptions. Healthcare workers were found to have a better knowledge about DM compared to the general population. Surprisingly, certain myths were prevalent even among healthcare workers. Conclusions. Certain myths and misconceptions have been pervasive in our society. Actions must be taken to dispel these misconceptions as they lead to an avoidable burden of disease. Therefore, people’s knowledge of DM needs to be enhanced through educational programs, social media, television, newspapers and campaigns

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially