Arif Hidayat

Studies on Nanostructure and Magnetic Behaviors of Mn-Doped Black Iron Oxide Magnetic Fluids Synthesized from Iron Sand

Manganese (Mn)-doped black iron oxide (Fe3O4) magnetic fluids in the system of MnxFe3−xO4 were successfully synthesized from natural magnetite (iron sand) by using co-precipitation method at room temperature. The analyses of the small angle neutron scattering (SANS) data by applying a log-normal sphere with a mass fractal models for x=0 and x=0.25 and two log-normal spheres with a single mass fractal models for x=0.5, 0.75 and 1 revealed that the primary particles of the MnxFe3−xO4 fluids tended to decrease from 3.8nm to 1.5nm along with the increasing fraction of Mn contents. The fractal dimension (D) increased from about 1.2 to 2.7 as the Mn contents were increasing; which physically represents an aggregation of the MnxFe3−xO4 particles in the fluids growing up from 1 to 3 dimensions to consolidate a more compact structure. The magnetization curves of the fluids exhibited an increasing saturation magnetization from x=0 to x=0.25, and a decreasing on x=0.5 and 0.75, with the maximum achievement of x=1. T...

The influence of iron- and copper- doped of PANi thin film on their structure and dielectric properties

Polyaniline (PANi) is one of conductive polymers which are widely studied. PANi has unique in the structure and physical properties that can be controlled by doping. In this work we report the role of CuCl2 and FeCl3 in the crystalline and dielectric properties of PANi/Ag films which was performed by means spin coating method. We employed sonochemical technic to form solutions of PANi ES II prior to spin coating method. The variation of FeCl3 and CuCl2 doped were used in the range of 0 M - 0.5 M. FTIR spectra of PANi EB and PANi ES clarified that the PANis were successfully synthesized. The crystallinity of the films were examined by menas of X-ray diffraction (XRD). While the polymeric grains were evaluated using SEM which is confirmed with the grain size analyses from X-RD data. Dielectric properties shows that introducing Fe and Cu doped could decrease their dielectric constant. The decreasing of dielectric constant was also achieved by increasing frequency.

Fabrication of PAN/ZnO Nanofibers by Electrospinning as Piezoelectric Nanogenerator

Piezoelectric nanogenerator is a material that is used for converting mechanical energy to electrical energy. This research aimed to study the piezoelectric nanogenerator properties in PAN/ZnO nanofibers layered on the stainless-steel substrate. ZnO nanoparticles that were used in this work were synthesized by coprecipitation method. The ZnO nanoparticles were mixed with PAN dissolved with DMF. Fabrication of PAN-ZnO nanofibers was done using the electrospinning method on the stainless-steel substrate. The formed PAN/ZnO nanofibers were then characterized using XRD, SEM, and FTIR. To test the piezoelectric nanogenerator properties, PAN/ZnO nanofibers were combined to PAN nanofibers and coated on the stainless-steel substrate to form piezoelectric nanogenerator device. This device was then connected to an electrometer and an oscilloscope to measure the current and voltage resulted after bending. The results of XRD of ZnO nanoparticles had the wurtzite crystal structure with the size of about 46 nm. Meanwhile, the PAN/ZnO had an amorphous structure. The test results of piezoelectric nanogenerator properties showed the value of voltage and current of 7.22 V and 47.48 μA, respectively. PAN/ZnO nanofibers on the stainless-steel substrate are potential to be the material of piezoelectric nanogenerators in general.

Shockley’s Equation Fit Analyses for Solar Cell Parameters from I-V Curves

Some of the technical problems that appear are obtaining solar cell parameters from I-V curve measurement data. One simple method is using linear graphical fit at zero current or voltage conditions. Although the accuracy of the obtained values is acceptable, other problems may arise regarding the number of parameters which could be obtained. We report a comparison between manual or graphical fit and fit using Shockley’s equation. The single I-V curve under the lighting was inferred to obtain the intrinsic parameters of the solar cells’ performance. The fittings were performed using the nonlinear equation of Shockley by determining some initial values of fittings such as Rs, Rsh, n, I0, Iph, and T. In the case of the Shockley equation fit, the iteration was performed several times to obtain the least possible inferred parameters. We have successfully obtained a better result of nonlinear Shockley fitting compared to the manual linear fit.

The Role of Fe2O3 and Light Induced on Dielectric Properties of Borosilicate Glass

Functionally glass materials have been widely applied in various technological applications remarkably due to their optoelectric properties. In this present study, the glass was prepared from leaching product of local silica sands. Bi2O3 and Na2CO3 were added to reduce the melting point of silica sand to form silica glass and Fe2O3/B2O3 was incorporated to examine its effect on the crystal structure, morphology, and light-induced dielectric properties of the borosilicate-based fuctional glass. The characterizations were conducted by means of Differential Thermal Analyses (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and capacitance meter under the influence of light intensity. The XRD pattern shows the absence of any sharp diffraction peak indicates the amorphous state of the borosilicate glass. While the SEM image shows that the borosilicate glass exhibited amorphous characteristic. Furthermore, the increasing of Fe2O3 tends to reduce the dielectric constant. On the other hand, the increase of light intensity increase the dielectric constant with a step like properties.

Effect of NiO and Light Intensity on Dielectric Constant of SiO2-B2O3-Bi2O3-Na2CO3 Glass Based on Silica Gel of Natural Sands

The use of silica in various fields is significantly increasing. One common application is silica based functional glass which has naturally show specific dielectric, optical, and magnetic properties. Many studies have been performing to explore the influence of dopant, composition, and other processing parameters as well as employing various characterization. In the previous work, we report the use of silica from silica sands. To reduce the melting temperature, we used silica sol-gel beside the utilization of some oxides such as B2O3, Na2CO3, and Bi3O3. We also used NiO as dopant explore the glass properties. We have prepared a series of sample with the composition of 50SiO2-25B2O3-(6.5-x) Bi3O3-18.5 Na2CO3-xNiO (x = 0, 1, 2, 3 and 4 wt%). After weighting process, the composition was blended, then heated to 450 °C for 120 minutes and then raised at 950 °C for 60 minutes in the crucible. Then samples of glass separated from the crucible and in the characterization of the structure using the DTA, XRD, SEM-EDAX and FTIR and measuring dielectric constant using a capacitance meter. The increase of NiO dopant resulted in increasing the dielectric constant of glass. On the other hand, the dielectric constant gradually decreases with the increase of light intensity. One can be noted that the applied intensity give rise to the step-like decrease of the dielectric constant. Whereas, the increasing magnetic field indicate the increase of dielectric constant.

Synthesis, Investigation on Structural and Magnetic Behaviors of Spinel M-Ferrite [M = Fe; Zn; Mn] Nanoparticles from Iron Sand

Spinel M-ferrite [M = Fe; Zn; Mn] nanoparticles were prepared from iron sand using a coprecipitation-sonochemical approach. The purified Fe3O4 from iron sand, ZnCl2 and MnCl2.4H2O, HCl, and NH4OH were used as raw materials. X-Ray Diffractometer (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), and Vibration Sample Magnetometer (VSM) were employed to characterize the crystal structure, functional groups, particle size, morphology, and magnetic behavior of the prepared samples, respectively. From the XRD data analysis, M-ferrite particles exhibited a single phase in spinel structure. Furthermore, the M-ferrite particle increased their lattice parameter and crystal volume tracking the metallic-ionic radii of M. The particle size of the M-ferrites particles varied with M, whereas the biggest and lowest were for Zn and Mn, respectively. Based on the magnetization curve, the M-ferrite nanoparticles tended to perform a superparamagnetic behavior and their saturation magnetization as a function of their M ion and particle size.

Preparation of Superparamagnetic Zn0.5Mn0.5Fe2O4 Particle by Coprecipitation-Sonochemical Method for Radar Absorbing Material

One of many applications of spinel ferrite nanoparticles is related to their performance as radar absorbing materials. In this work, we report developing synthesis method through combined coprecipitation-sonochemical routes in preparing Zn0.5Mn0.5Fe2O4 nanoparticle from iron sand in Indonesia as a vital raw material. The structure, size, morphology, and elements of the Zn0.5Mn0.5Fe2O4 nanoparticle were investigated via X-Ray diffractometry and Transmission/Scanning Electron Microscopy (TEM/SEM) combining Energy Dispersive Spectroscopy (EDS). The magnetic properties of the Zn0.5Mn0.5Fe2O4 nanoparticle were characterized by using Vibrating Sample Magnetometer (VSM). Furthermore, the reflection loss character of the Zn0.5Mn0.5Fe2O4 nanoparticle was determined via Vector Network Analyzer (VNA). From the qualitative and quantitative analysis of the XRD data, it can be identified that the Zn0.5Mn0.5Fe2O4 particle formed a spinel cubic structure in a single phase with the lattice parameter of approximately 8.401 A. It is known from the TEM image that the Zn0.5Mn0.5Fe2O4 particle had a size of about 9.7 nm and tended to agglomerate. Furthermore, the data analysis of the M(H) curve presented that the Zn0.5Mn0.5Fe2O4 nanoparticle has a superparamagnetic behavior with the saturation magnetization of approximately 43 emu/g. Finally, the data analysis of the reflection loss as a function of frequency showed that the Zn0.5Mn0.5Fe2O4 nanoparticle performs as a radar absorbing material with the absorption performance of approximately -11.0 dB at the frequency of 10.8 GHz

Optical Properties of Fe3O4 Magnetic Fluid from Iron Sand

Nowadays, a high sensitive sensor for the magnetic field has become an essential tool that vastly desired in several fields, especially in biomedical application. Therefore, the development of preparing material for the magnetic sensor becomes crucial to be conducted. In this experimnet, we propose the use of Fe3O4 magnetic fluid prepared from a local iron sand in Indonesia as a material for a magnetic sensor. In this work, optical activities of the Fe3O4 magnetic fluid as the effect of magneto-optics were performed under varying external magnetic field. The polarization direction change of the laser was detected as a function of the external magnetic field with the exponential function. Moreover, the intensity collected by a photodetector exhibited a linear correlation with the external magnetic field. These phenomena become strong evidence that the prepared Fe3O4 magnetic fluid opens potential to be applicated further as sensors, especially as a high sensitive optics-based sensor for the magnetic field.

Fabrication of Magnetite Nanoparticles Dispersed in Olive Oil and Their Structural and Magnetic Investigations

In this work, the iron sand taken from Wedi Ireng Beach in Banyuwangi, Indonesia, was employed as the main precursor in fabricating magnetite nanoparticles. The magnetite nanoparticles were then functionalized in preparing magnetic fluids coated by oleic acid as a surfactant and dispersed in olive oil as a liquid carrier. The phase purity, crystallite size and crystal structure of the dried magnetic fluids were characterized by using X-Ray Diffractometer. Meanwhile, the functional groups of the magnetic fluids were investigated by means of Fourier Transform Infra-Red (FTIR) spectroscopy. The particle size and morphology of the magnetite particles were also investigated by using Transmission Electron Microscopy (TEM). The magnetic behaviors of the magnetic fluids were determined by using Vibrating Sample Magnetometer (VSM). Based on the XRD data analysis, the magnetite particles crystallized in the spinel structure without the presence of any other phases. The FTIR spectra showed that the functional groups of the magnetic fluids were referring to the magnetite, oleic acid, and olive oil. The TEM image presented that the magnetite particle was formed in a nanometric size. Finally, the saturation magnetization of the magnetic fluids varied in the mass composition and particle size of the magnetite nanoparticles.