Document Type : Research Paper
Authors
1 Directorate General of Education Karkh 3, Ministry of Education, Baghdad, Iraq
2 Department of Clinical Laboratory Science, College of Pharmacy, Al-Nahrain University, Baghdad, Iraq
3 Department of Physics, College of Science, Al-Nahrain University, Baghdad, Iraq
Abstract
Keywords
INTRODUCTION
Material characters enactment progress for the previous decades was the crucial aim of several experts [1-11] for evolving such features because of their enormous uses in many sectors of manufactures. Ferrites have been one of such materials that were examined extensively in large [12,13] . Plasmas as thermal (equilibrium) were utilized for processing of material for 100 years and more. One TP mutual example in processing of material is electric welding. Generally, electrical power mostly utilized for igniting plasma is convertion into heat, thus, TPs able to surfaces melting of metallic besides the electrodes utilized for plasma ignition. Nevertheless, it is not desirable to have this extra heat in contact with the softer surfaces or heat-sensitive utilized in processing of material, i.e., cleaning, coating, and etching. For such applications, plasmas being cold might be a worthy substitute, as the e- are of energy as thermal being high; wherease species as heavier stay “cold”. So, generally industrial technology of large-scale is related to non-TPs ignited at low or minimized pressures of gas, where the temperature of neutral gas is enough low for preventing processing materials damage. Also, there is a history of utilizing plasmas as non-thermal (non-equilibrium) in materials processing; nevertheless, utilizing atmospheric plasmas pressure (APPs) to pereform so is modern. Such approach as innovative to processing of material is appealing as a result of simplicity, less cost, combination and of range of wide possibilities for modification surface and treatment [14,15].
Based on the position of metallic ion, 3 spinel ferrite types are there: spinel ferrite as normal, reverse and random. The parameters of ferrite can be controlled through choosing appropriate synthesis technique along with suitable preparation conditions [12]. Diverse synthesis techniques were utilized to make spinel ferrites, 2 main diverse routes to synthesis a material, conventional ceramic process and non-conventional wet chemical processs include the process as sol-gel [13]. Also, such process is known as the chemical deposition solution process that is widely utilized for the nanomaterials synthesis starting from chemical (sol) solutions named precursors. Precursors mostly are metal alkoxides and chlorides that refer to diverse polycondensation and hydrolysis reactions forms [16]. The formed gel through such process proceeds in lengthy time for drying. Also, it needs high ST (over 1000 °C) for lengthy time to attain phase of purity. The materials as raw, [Zn (NO3)2.6H2O, Cu (NO3)2.6H2O, Fe (NO3)3.9H2O], were chosen with so great purity for avoiding whichever impact on the characters of compound. (Cu1-xZnxFe2O4) formula as ferrite was utilized if X = 0.4 to make the samples Cu0.6Zn0.4Fe2O4 through a process of sol-gel in which the best findings seemed at such value.
Mathematical formula for the association between the voltage and the current waveforms is resultant from the Telegraphists formulas. A coefficient of reflection ρ or Γ is definite as the ratio of reflected wave to the wave as incident [17]:
Generally, considering the ne2rk as 2-port, there will be propagating waves into and out of every port. Once there is device linear, the waves of output can be defined in input waves terms as following [18]:
The parameters of S are constantly dignified in the values as decibel form dB, and for convertion such parameters are in form as (%); one should utilize the formulas 2 and 3 to find [19,20]:
The absorbance % is found through substituting the results of formula 4 and 5 in the formula:
and the attenuation reflection or coefficient loss in dB units is measured from the formula:
The TE process includes evaporating materials source in chamber as vacuumed less than10-6 torr and condensation for the particles being evaporated on substrates. In such method, energy as thermal is provided to materials source from where evaporated atoms are for deposited on the substrates. The deposition flux or rate is a travel distance function from the source to the substrates, the impingement angle onto the surface of substrate, the temperature of substrate T.S. and the pressure as base. The thin film ferrite spinel was maked utilizing the «Edward 300» coating system. The evaporation chamber consists of a basic form of cover, heating poles, evaporation boat, substrate holder and vacuum unit [21].
MATERIALS AND METHODS
The sol-gel technique was utilized to make (Cu1-xZnxFe2O4) ferrite[16], in which the amounts of the C₆H₈O₇ and NO3- measured based on their atomic/MW. The raw material utilized in samples formation were variegated with 80 ml DW in a beaker that was homogenized through stirring as continuous with the model (LMS-1003) as hot plat-stirrers as magnetic.
The solution pH was adjusted to (~7) utilizing solution of ammonia and heating on a hot plate for ½ h at 60 °C. The temperature is increased to 80 ºC with heating as continuous after around 3hrs. Initially, such sol was changed to a gel. Drying was done to the gel was at 120 °C till burntting in a self combustion propagating fashion till all gels were burnt out completely to form a structure that loose fluffy. The material as fluffy was crushed to find ferrite powder utilizing the grinder as electric for 3 min. The ash as as-burnt at 500 °C was calcined for three h to find better homogeneous and crystallization cation distribution in the crystallite as spinel. The powder is variegated with material as glycerin of 6 wt. % with 88% purity as a binder. Attended 2 samples for the ferrite formula (Table 1), and the samples were sintered for 6 hrs at STs 1050 °C with the heating rate 50 °C/min, after that they were lefted to be cooled spontaneously in the furnace inside.
After preparation samples through sol-gel process, thin films was deposited on the Al Al3 substrates after calculation the mass required to be employed as powder of the ferrite in vaporizer device and after that make the accurate form to get the needed diverse thicknesses with no addition of whichever fixative or adhesive materials [19]. The collected samples inside a cavity were placed for oxidation and moisture prevention, after that inspection the magnetic characters through vector analyzer ne2rk (VNA).
In the current work, the line of Transmission/Reflection process was utilized to check the microwave maked samples absorbance. Such process includes sample placing in a coaxial or waveguide section line and measuring the 2 parameters as ports complex scattering with a VNA and the calibration should be done prior to measurements preformance. Also, this process includes reflected measurement (S11) and signal as transmitted (S21). The parameters of relevant scattering closely relate to the complex material permeability and permittivity through formulas. The S-parameters conversion to parameter as complex dielectric is computed through solving the formulas utilizing a program. In numerous cases, the process needs preparation the sample i.e., machining as the sample tightly fit into the coaxial or waveguide line [5] 0.1, 0.3, 0.4, 0.5, 0.6 [22]we investigate the possibility of using the heterogeneous materials, with cuboid metallic inclusions inside a dielectric substrate (host. Thin films thickness were measured through estimated wt. process; measured the substrate wt. prior to the deposition of the film, the wt. following film deposition on the substrate, and the difference in wt. (∆m) represents the film wt. Thickness might be achieved utilizing the law of mass [23].
RESULTS AND DISCUSSION
To investigating the crystal made samples structure following sintering, the analysis of phase was pereformed through system of SHIMADZU XRD-6000 that utilizing radiation of Cu-Kα with 1.54060 Aᵒ wavelength λ and the range of angles of Braggs are 2θ=5˚- 80˚. XRD analysis is illustraten in Fig. 1 for Cu0.6Zn0.4Fe2O4 sample that maked at ST 1050 °C with the 0.4 value of x and t= 400 ±20 nm. The findings of this figure illustrating that the structure of the sample is poly-crystalline nature having the cubic thin prepared film phase along acute and peaks as very fine mentioning a worthy crystallization with the chief peak along (311) plane at 2θ =35.461ᵒ. The Millar indices (h,k,l) values that diffract for X-ray are (111), (200), (211), (202), (222), and (220) (Fig. 1).
The distance between levels of crystalline (d) was measured through utilizing equation of Bragg [24,25]:
and the crystallite average size (C.S) estimated utilizing equation of Scherer [24,25]:
In which Δ is width as full at 1/2 maximum in units of radian, λ is the x-ray wavelength (Aº), θ is Braggs diffraction XRD peak angle (degree). The micro strains (M.S) measured from the following [28,29]:
The results of XRD are totally matched with the (ASTM) as international standard which presented in Table 2 that indicated to the cubic spinel nano-structure formation.
For investigation the growth quality, grains distribution and Cu-Zn thin roughness films, AFM surface topography 400±20 nm images thickness taken in a mode as contact on a scan sample size (Figure 2). The thin film surface is roughly homogeneous and smooth, microcracks free, holes or pores. Smooth surfaces with roughness being low are essential for the needed physical device applications characters. We measured the roughness average (Ra = 5.3 nm) and thin-film roughness root mean square (Rq = 7.09 nm) from the micrographs of atomic force from the AFM line profiles. The thin film was grown to contain grains of diverse shapes, so the height variation of surface was around 31.2 nm.
SEM of thin film 400±20 nm thickness Cu-Zn ferrite on Al substrate is illustrated in Fig. 3. The micrograph as cross-section illustrats particles, which agglomerated and grown regularly on the substrate. The thin film of Cu-Zn ferrite has enclosed the complete surface of substrate along some random particles overgrowth as proved through the micrographs. From the micrographs of surface, one able to observe that the thin films surface have spherical nano-composite grains of size almost regular and substrates enclosing. It might also be noticed high homogeneousness of surface (such as of good homogeneity) with no defects. The size of grain measured from SEM is found to be of 45.93 nm order that is in good covenant with the size of particle obtained from XRD. The particles growth was related to the surface sintering and diffusion mechanisms at temperatures being high. In the process of sintering, as the temperature elevated, the particles are joined on the surface to each other through mechanism as necking to minimize their surface energy. Such process lasts till the particles are welding to findher[30]–[32]. Thus, the particles surface area and pores are declined throughout the process of sintering.
The microwave absorbance characters of Cu1-xZnxFe2O4 ferrite samples that made through sol-gel process and in 1050 oC sintered and then placed in TE system vacuum on Al3 substrates for thicknesses of (400,800) ±20 nm were verified for X-band (8-12.5 GHz) through system of VNA.
Fig. 4 illustrate the absorbance values are very high at 800 nm thickness and the bandwidth being good is (8.40) GHz for region of X- band either bandwidth being good at 800 nm is 9.10 GHz for the range of frequency (8.40-8.61) and (10.21-11.03) GHz, and bandwidth being good at 400 nm is 8.61 GHz for the range frequency (8.20-9.25) and (11.20-11.60) GHz.
Fig. 5 illustrates the coefficient of attenuation as a frequency function. The figure similarities in stability and volatility indicating lack of Zn.
Fig. 6 illustrates the coefficient of reflection as a frequency function to (400 & 800)±20 nm CuO.6ZnO.4Fe2O4 thickness made samples. Such figure indicated an excellent result of the 2 diverse samples thicknesses if the findings of coefficient of reflection near zero value that means that the reflection is so small. From the figure, 2 peaks of resonance appearance are there at 8.41 GHz that are regarded as not normal, and observed that the coefficient of reflection best values was at 800 nm because of the ferrite completion, besides because of increased density that minimizes the porosity. The highest coefficient of reflection values at 800 nm are (-7.16, -3.96) dB at frequencies (8.42, 8.66) GHz, correspondingly.
Fig. 7 illustrates that there are transmission coefficient overlap values for the 2 (400 and 800) ±20 nm thicknesses that approves the ferrite development of in 2 thicknesses. One peak of resonance is there for Cu0.6Zn0.4Fe2O4 800 nm and 400 nm thicknesses of sample sintered at 1050°C and such peak is formed if there is corresponding in the relative permeability and relative ferrite permittivity. Also we are able to notice that the coefficient of values of attenuation is so good because of the ferrite completion and increased density that minimizes the porosity. The maximum coefficient values of attenuation are (-9.57,-9.89) dB at (9.58, 12.45) GHz frequencies, correspondingly.
CONCLUSIONS
For the currrent work, Cu-Zn ferrite nano-composite thin films were obtained successfully through the sol-gel process and utilizing the vacuum TE technique to ferrite deposition on Al substrates. XRD- diffraction illustrates a polycrystalline samples structure and the pattern of reflections matching to the planes of (111), (200), (211), (202), and (220) with the chief reflection with (211) plane. Images of AFM expose smooth with low roughness of surface. Images of SEM describe surface of high consistency for the made samples. The samples that deposited offered a good stability and steadier besides, the ferrite absorbance, which deposited on the substrates of Al elevating in higher thickness, while transmission and reflection declining. This work proves the utilizing possibility of thin films spinel ferrite that made through utilizing the sol-gel process with appropriate thickness for devices of microwave, devices of optoelectronic, and many other applications of microwave.
CONFLICT OF INTEREST
The authors declare that there is no conflict of interests regarding the publication of this manuscript.