Surface Roughness-Induced Changes in Important Physical Features of CoFeSm Thin Films on Glass Substrates during Annealing.

Co60Fe20Sm20 thin films were deposited onto glass substrates in a high vacuum setting. The films varied in thickness from 10 to 50 nm and underwent annealing processes at different temperatures: room temperature (RT), 100, 200, and 300 °C. Our analysis encompassed structural, magnetic, electrical, nanomechanical, adhesive, and optical properties in relation to film thickness and annealing temperature. X-ray diffraction (XRD) analysis did not reveal characteristic peaks in Co60Fe20Sm20 thin films due to insufficient growth-driving forces. Electrical measurements indicated reduced resistivity and sheet resistance with increasing film thickness and higher annealing temperatures, owing to hindered current-carrier transport resulting from the amorphous structure. Atomic force microscope (AFM) analysis showed a decrease in surface roughness with increased thickness and annealing temperature. The low-frequency alternating current magnetic susceptibility (χac) values increased with film thickness and annealing temperature. Nanoindentation analysis demonstrated reduced film hardness and Young's modulus with thicker films. Contact angle measurements suggested a hydrophilic film. Surface energy increased with greater film thickness, particularly in annealed films, indicating a decrease in contact angle contributing to this increase. Transmittance measurements have revealed intensified absorption and reduced transmittance with thicker films. In summary, the surface roughness of CoFeSm films at different annealing temperatures significantly influenced their magnetic, electrical, adhesive, and optical properties. A smoother surface reduced the pinning effect on the domain walls, enhancing the χac value. Additionally, diminished surface roughness led to a lower contact angle and higher surface energy. Additionally, smoother surfaces exhibited higher carrier conductivity, resulting in reduced electrical resistance. The optical transparency decreased due to the smoother surface of Co60Fe20Sm20 films.

Thickness, Annealing, and Surface Roughness Effect on Magnetic and Significant Properties of Co40Fe40B10Dy10 Thin Films.

In this study, Co40Fe40B10Dy10 thin films were deposited using a direct current (DC) magnetron sputtering technique. The films were deposited on glass substrates with thicknesses of 10, 20, 30, 40, and 50 nm, and heat-treated in a vacuum annealing furnace at 100, 200, and 300 °C. Various instruments were used to examine and analyze the effects of roughness on the magnetic, adhesive, and mechanical properties. From the low frequency alternating current magnetic susceptibility (χac) results, the optimum resonance frequency is 50 Hz, and the maximum χac value tends to increase with the increase in the thicknesses and annealing temperatures. The maximum χac value is 0.18 at a film thickness of 50 nm and an annealing temperature of 300 °C. From the four-point probe, it is found that the resistivity and sheet resistance values decrease with the increase in film deposition thicknesses and higher annealing temperatures. From the magnetic force microscopy (MFM), the stripe-like magnetic domain distribution is more obvious with the increase in annealing temperature. According to the contact angle data, at the same annealing temperature, the contact angle decreases as the thickness increases due to changes in surface morphology. The maximal surface energy value at 300 °C is 34.71 mJ/mm2. The transmittance decreases with increasing film thickness, while the absorption intensity is inversely proportional to the transmittance, implying that the thickness effect suppresses the photon signal. Smoother roughness has less domain pinning, more carrier conductivity, and less light scattering, resulting in superior magnetic, electrical, adhesive, and optical performance.

Investigation of Sm Addition on Microstructural and Optical Properties of CoFe Thin Films.

CoFe-based alloys and rare earth (RE) elements are among the most studied materials in applying magnetic devices to improve soft magnetic characteristics. A series of Co40Fe40Sm20 films are deposited on a glass substrate via the sputtering technique, followed by an annealing process to investigate their effect on microstructural and optical properties of Co40Fe40Sm20 films. In this study, the increase in the thickness of Co40Fe40Sm20 films and annealing temperatures resulted in a smoother surface morphology. The 40 nm Co40Fe40Sm20 films annealed 300 °C are expected to have good wear resistance and adhesive properties due to their high values of H/E ratio and surface energy. Optical transparency also increased due to the smoother surface of the Co40Fe40Sm20 films.

Controllable Doping Characteristics for WSxSey Monolayers Based on the Tunable S/Se Ratio.

Transition metal dichalcogenides (TMDs) have attracted much attention because of their unique characteristics and potential applications in electronic devices. Recent reports have successfully demonstrated the growth of 2-dimensional MoSxSey, MoxWyS2, MoxWySe2, and WSxSey monolayers that exhibit tunable band gap energies. However, few works have examined the doping behavior of those 2D monolayers. This study synthesizes WSxSey monolayers using the CVD process, in which different heating temperatures are applied to sulfur powders to control the ratio of S to Se in WSxSey. Increasing the Se component in WSxSey monolayers produced an apparent electronic state transformation from p-type to n-type, recorded through energy band diagrams. Simultaneously, p-type characteristics gradually became clear as the S component was enhanced in WSxSey monolayers. In addition, Raman spectra showed a red shift of the WS2-related peaks, indicating n-doping behavior in the WSxSey monolayers. In contrast, with the increase of the sulfur component, the blue shift of the WSe2-related peaks in the Raman spectra involved the p-doping behavior of WSxSey monolayers. In addition, the optical band gap of the as-grown WSxSey monolayers from 1.97 eV to 1.61 eV is precisely tunable via the different chalcogenide heating temperatures. The results regarding the doping characteristics of WSxSey monolayers provide more options in electronic and optical design.

The Influence of Annealing and Film Thickness on the Specific Properties of Co40Fe40Y20 Films.

Cobalt Iron Yttrium (CoFeY) magnetic film was made using the sputtering technique in order to investigate the connection between the thickness and annealing procedures. The sample was amorphous as a result of an insufficient thermal driving force according to X-ray diffraction (XRD) examination. The maximum low-frequency alternate-current magnetic susceptibility (χac) values were raised in correlation with the increased thickness and annealing temperatures because the thickness effect and Y addition improved the spin exchange coupling. The best value for a 50 nm film at annealing 300 °C for χac was 0.20. Because electron carriers are less constrained in their conduction at thick film thickness and higher annealing temperatures, the electric resistivity and sheet resistance are lower. At a thickness of 40 nm, the film's maximum surface energy during annealing at 300 °C was 28.7 mJ/mm2. This study demonstrated the passage of photon signals through the film due to the thickness effect, which reduced transmittance. The best condition was found to be 50 nm with annealing at 300 °C in this investigation due to high χac, strong adhesion, and low resistivity, which can be used in magnetic fields.

Effect of Annealing and Thickness of Co40Fe40Yb20 Thin Films on Various Physical Properties on a Glass Substrate.

The aim of this work is to investigate the effect of annealing and thickness on various physical properties in Co40Fe40Yb20 thin films. X-ray diffraction (XRD) was used to determine the amorphous structure of Co40Fe40Yb20 films. The maximum surface energy of 40 nm thin films at 300 °C is 34.54 mJ/mm2. The transmittance and resistivity decreased significantly as annealing temperatures and thickness increased. At all conditions, the 10 nm film had the highest hardness. The average hardness decreased as thickness increased, as predicted by the Hall-Petch effect. The highest low-frequency alternative-current magnetic susceptibility (χac) value was discovered when the film was annealed at 200 °C with 50 nm, and the optimal resonance frequency (ƒres) was in the low frequency range, indicating that the film has good applicability in the low frequency range. At annealed 200 °C and 50 nm, the maximum saturation magnetization (Ms) was discovered. Thermal disturbance caused the Ms to decrease when the temperature was raised to 300 °C. The optimum process conditions determined in this study are 200 °C and 50 nm, with the highest Ms, χac, strong adhesion, and low resistivity, which are suitable for magnetic applications, based on magnetic properties and surface energy.

The Influence of Oxidation on the Magnetic, Electrical, and Mechanical Properties of Co40Fe40Yb20 Films.

A typical body-centered cubic (BCC) CoFe(110) peak was discovered at approximately 2θ = 44.7°. At 2θ = 46°, 46.3°, 47.7°, 55.4°, 54.6°, and 56.4°, the Yb2O3 and Co2O3 oxide peaks were visible in all samples. However, with a heat treatment temperature of 300 °C, there was no typical peak of CoFe(110). Electrical characteristics demonstrated that resistivity and sheet resistance reduced dramatically as film thickness and annealing temperatures increased. At various heat treatments, the maximum hardness was 10 nm. The average hardness decreased as the thickness increased, and the hardness trend decreased slightly as the annealing temperature was higher. The highest low-frequency alternative-current magnetic susceptibility (χac) value was discovered after being annealed at 200 °C with 50 nm, and the optimal resonance frequency (fres) was discovered to be within the low-frequency range, indicating that the Co40Fe40Yb20 film can be used in low-frequency applications. The maximum saturation magnetization (Ms) was annealed at 200 °C for 50 nm. Thermal disturbance caused the Ms to decrease as the temperature reached to 300 °C. The results show that when the oxidation influence of as-deposited and thinner films is stronger than annealing treatments and thicker thickness, the magnetic and electrical properties can be enhanced by the weakening peak of the oxide, which can also reduce interference.

Effects of Annealing and Thickness of Co60Fe20Yb20 Nanofilms on Their Structure, Magnetic Properties, Electrical Efficiency, and Nanomechanical Characteristics.

X-ray diffraction (XRD) analysis showed that metal oxide peaks appear at 2θ = 47.7°, 54.5°, and 56.3°, corresponding to Yb2O3 (440), Co2O3 (422), and Co2O3 (511). It was found that oxide formation plays an important role in magnetic, electrical, and surface energy. For magnetic and electrical measurements, the highest alternating current magnetic susceptibility (χac) and the lowest resistivity (×10-2 Ω·cm) were 0.213 and 0.42, respectively, and at 50 nm, it annealed at 300 °C due to weak oxide formation. For mechanical measurement, the highest value of hardness was 15.93 GPa at 200 °C in a 50 nm thick film. When the thickness increased from 10 to 50 nm, the hardness and Young's modulus of the Co60Fe20Yb20 film also showed a saturation trend. After annealing at 300 °C, Co60Fe20Yb20 films of 40 nm thickness showed the highest surface energy. Higher surface energy indicated stronger adhesion, allowing for the formation of multilayer thin films. The optimal condition was found to be 50 nm with annealing at 300 °C due to high χac, strong adhesion, high nano-mechanical properties, and low resistivity.

Effect of Yttrium Addition on Structure and Magnetic Properties of Co60Fe20Y20 Thin Films.

In this paper, a Co60Fe20Y20 film was sputtered onto Si (100) substrates with thicknesses ranging from 10 to 50 nm under four conditions to investigate the structure, magnetic properties, and surface energy. Under four conditions, the crystal structure of the CoFeY films was found to be amorphous by an X-ray diffraction analyzer (XRD), suggesting that yttrium (Y) added into CoFe films and can be refined in grain size and insufficient annealing temperatures do not induce enough thermal driving force to support grain growth. The saturation magnetization (MS) and low-frequency alternate-current magnetic susceptibility (χac) increased with the increase of the thicknesses and annealing temperatures, indicating the thickness effect and Y can be refined grain size and improved ferromagnetic spin exchange coupling. The highest Ms and χac values of the Co60Fe20Y20 films were 883 emu/cm3 and 0.26 when the annealed temperature was 300 °C and the thickness was 50 nm. The optimal resonance frequency (fres) was 50 Hz with the maximum χac value, indicating it could be used at a low frequency range. Moreover, the surface energy increased with the increase of the thickness and annealing temperature. The maximum surface energy of the annealed 300 °C film was 30.02 mJ/mm2 at 50 nm. Based on the magnetic and surface energy results, the optimal thickness was 50 nm annealed at 300 °C, which has the highest Ms, χac, and a strong adhesion, which can be as a free or pinned layer that could be combined with the magnetic tunneling layer and applied in magnetic fields.

Annealing Effect on the Characteristics of Co40Fe40W10B10 Thin Films on Si(100) Substrate.

This research explores the behavior of Co40Fe40W10B10 when it is sputtered onto Si(100) substrates with a thickness (tf) ranging from 10 nm to 100 nm, and then altered by an annealing process at temperatures of 200 °C, 250 °C, 300 °C, and 350 °C, respectively. The crystal structure and grain size of Co40Fe40W10B10 films with different thicknesses and annealing temperatures are observed and estimated by an X-ray diffractometer pattern (XRD) and full-width at half maximum (FWHM). The XRD of annealing Co40Fe40W10B10 films at 200 °C exhibited an amorphous status due to insufficient heating drive force. Moreover, the thicknesses and annealing temperatures of body-centered cubic (BCC) CoFe (110) peaks were detected when annealing at 250 °C with thicknesses ranging from 80 nm to 100 nm, annealing at 300 °C with thicknesses ranging from 50 nm to 100 nm, and annealing at 350 °C with thicknesses ranging from 10 nm to 100 nm. The FWHM of CoFe (110) decreased and the grain size increased when the thickness and annealing temperature increased. The CoFe (110) peak revealed magnetocrystalline anisotropy, which was related to strong low-frequency alternative-current magnetic susceptibility (χac) and induced an increasing trend in saturation magnetization (Ms) as the thickness and annealing temperature increased. The contact angles of all Co40Fe40W10B10 films were less than 90°, indicating the hydrophilic nature of Co40Fe40W10B10 films. Furthermore, the surface energy of Co40Fe40W10B10 presented an increased trend as the thickness and annealing temperature increased. According to the results, the optimal conditions are a thickness of 100 nm and an annealing temperature of 350 °C, owing to high χac, large Ms, and strong adhesion; this indicates that annealing Co40Fe40W10B10 at 350 °C and with a thickness of 100 nm exhibits good thermal stability and can become a free or pinned layer in a magnetic tunneling junction (MTJ) application.

Impact of Annealing on Magnetic Properties and Structure of Co40Fe40W20 Thin Films on Si(100) Substrate.

Co40Fe40W20 monolayers of different thicknesses were deposited on Si(100) substrates by DC magnetron sputtering, with Co40Fe40W20 thicknesses from 10 to 50 nm. Co40Fe40W20 thin films were annealed at three conditions (as-deposited, 250 °C, and 350 °C) for 1 h. The structural and magnetic properties were then examined by X-ray diffraction (XRD), low-frequency alternative-current magnetic susceptibility (χac), and an alternating-gradient magnetometer (AGM). The XRD results showed that the CoFe (110) peak was located at 2θ = 44.6°, but the metal oxide peaks appeared at 2θ = 38.3, 47.6, 54.5, and 56.3°, corresponding to Fe2O3 (320), WO3 (002), Co2O3 (422), and Co2O3 (511), respectively. The saturation magnetization (Ms) was calculated from the slope of the magnetization (M) versus the CoFeW thickness. The Ms values calculated in this manner were 648, 876, 874, and 801 emu/cm3 at the as-deposited condition and post-annealing conditions at 250, 350, and 400 °C, respectively. The maximum MS was about 874 emu/cm3 at a thickness of 50 nm following annealing at 350 °C. It indicated that the MS and the χac values rose as the CoFeW thin films' thickness increased. Owing to the thermal disturbance, the MS and χac values of CoFeW thin films after annealing at 350 °C were comparatively higher than at other annealing temperatures. More importantly, the Co40Fe40W20 films exhibited a good thermal stability. Therefore, replacing the magnetic layer with a CoFeW film improves thermal stability and is beneficial for electrode and strain gauge applications.

Effect of Annealing on the Structural, Magnetic and Surface Energy of CoFeBY Films on Si (100) Substrate.

The structure, magnetic properties, optical properties and adhesion efficiency of CoFeBY films were studied. Co40Fe40B10Y10 alloy was sputtered onto Si (100) with a thickness of 10-50 nm, and then annealed at room temperature, 100 °C, 200 °C and 300 °C for 1 h. X-ray diffraction (XRD) showed that the CoFeBY films deposited at room temperature are amorphous. Annealing at 100 °C gave the films enough thermal energy to change the structure from amorphous to crystalline. After annealing, the CoFeBY thin film showed a body-centered cubic (BCC) CoFeB (110) characteristic peak at 44°. However, the low-frequency alternative-current magnetic susceptibility (χac) and saturation magnetization (MS) increased with the increase of thickness. CoFeBY thin films had the highest χac and MS after annealing at 300 °C compared to that at other temperatures. After annealing at 300 °C, the surface energy of CoFeBY film is the maximum at 50 nm. Higher surface energy indicated stronger adhesion.

Structure and Magnetic Properties of Co40Fe40V20 Thin Films.

This study investigated the structure and magnetic properties of Co40Fe40V20 thin films with a thicknesses (tf) of 10 nm to 100 nm on a glass substrate. The X-ray diffraction (XRD) patterns of the CoFeV films demonstrated a significant crystalline body-centered cubic (BCC) CoFe (110) structure when the thickness was between 60 and 100 nm, and an amorphous status were shown when the thickness was from 10 to 50 nm. The strongest crystalline XRD peak was at 60 nm because it had a continuous mode of film growth and induced a large grain distribution. The low-frequency alternating current magnetic susceptibility (Ï°ac) property decreased when the frequency increased. The lowest Ï°ac value was detected at 60 nm owing to the large grain distribution inducing high coercivity (Hc) and then enhancing the spin coupling strength. The external field (Hext) was difficult to rotate spin state, then deduces the spin sensitivity and Ï°ac value is decreased. The highest Ï°ac meant the spin sensitivity was maximized at the optimal resonance frequency. The 50-mm thickness had the highest Ï°ac 0.045 value at an fres of 100 Hz. The fres value was less than 1000 Hz at all CoFeV thicknesses, suggesting that CoFeV films would be suitable for low-frequency magnetic component applications. Moreover, the saturation magnetization (Ms) revealed a thickness effect when the thicknesses had a larger Ms. The Hc values were between 3 Oe and 10 Oe at all CoFeV films, except for 60 nm. The Hc of the 60 nm film was about 80 Oe due to the larger grain distribution, and it induced strong remanent magnetization (Mr) and a larger squareness ratio (Mr/Ms) of 92%. The results of the magnetic measurement showed that the 60 nm Co40Fe40V20 film had greater Hc and a good squareness ratio.

Ta and Ru Seed Layers Effect on the Crystallinity and Wettability of Co60Fe20V20 Films.

The following structures are deposited under the conditions (a) glass/Ru(X nm)/Co60Fe20V20(5 nm) and (b) glass/Ta(Y nm)/Co60Fe20V20(5 nm) at room temperature (RT), where X and Y is from 5 nm to 10 nm. X-ray diffraction (XRD) patterns of glass/Ru(X nm)/Co60Fe20V20(5 nm) and glass/Ta(Y nm)/Co60Fe20V20(5 nm) reveal a weak crystallization at peak ß-(200) as the thicknesses of Ta increase from 8 nm to 10 nm, and the patterns indicate an amorphous state as the thicknesses of all Ru films and Ta thicknesses increase from 5 nm to 7 nm. The average contact angles of glass/Ru(X nm)/Co60Fe20V20(5 nm) and glass/Ta(Y nm)/Co60Fe20V20(5 nm) are less than 90° with testing liquids deionized (DI) water and glycerol. The average contact angle of water on the surface is nearly 90 degrees, indicating it is hydrophobic. Moreover, the maximum surface energy of glass/Ru(9 nm)/Co60Fe20V20(5 nm) and glass/Ta(10 nm)/Co60Fe20V20(5 nm) are 44.5 mJ/m2 and 37.4 mJ/m2, demonstrating that the high surface energy corresponds to a strong adhesion, which can be combined with a magnetic tunneling layer of MgO or AlOx and is compatible with other semiconductor processes in magnetic recording media and photoelectric applications.

Microstructure, In-Plane Magnetic Properties, and Surface Energy of Co60Fe20V20 Thin Films.

Co60Fe20V20 thin films with thicknesses ranging from 3 to 13 nm were sputtered onto a Si(100) substrate at room temperature (RT). Captured selected-area diffraction patterns (SADs) and high-resolution cross-sectional transmission electron microscopy (HR X-TEM) images revealed that the microstructures of the Co60Fe20V20 thin films were amorphous. The hysteresis loop of the thinner Co60Fe20V20 thin films displayed the in-plane magnetic anisotropy, possibly as a result of atmo-spheric exposure. A comparison of saturation magnetization (Ms) and thicknesses indicated a concave-down phenomenon due to magnetic coupling. In addition, the coercivity (Hc) also suggested a concave-down trend because the thinner Co60Fe20V20 thin films had a greater pining sites effect and rendered the domain wall difficult to move, resulting in higher Hc and lower Ms. The contact angles were smaller than 90°, indicating that the films were hydrophilic. The surface energy, which had a close positive correlation with adhesion ranged from 22.3 to 33.3 mJ/mm2 and displayed a concave-up trend. The critical thickness was 5 nm. Based on the magnetic and surface energy results, the optimal thickness of Co60Fe20V20 films is 7 nm due to high Ms, low Hc, and strong adhesion. They are suitable for use as a free layer of the magnetic tunneling junction and can be applied in magnetic recording media.

Effect of (102) Diffracted Peak on Magnetic, Photoelectric, and Adhesive Characteristics of Fe2Si Films.

Fe2Si films with thicknesses from 100 nm to 600 nm underwent the following processes; (a) as-deposited films were maintained at room temperature (RT); (b) deposited films were post-annealed at 150 °C for 1 h, and (c) deposited films were post-annealed at a treatment temperature of 250 °C for 1 h. The X-ray diffraction (XRD) patterns of Fe2Si included significant (102) and (200) diffractions with corresponding peaks at 2∅are 44° and 53°, respectively. The (102) diffracted intensity and grain size of thicker and post-annealed Fe2Si thin films exceeded those of thinner and as-deposited Fe2Si thin films. The Fe2Si (102) peak revealed magneto-crystalline anisotropy, which reduced electrical resistivity and was associated with the highest low-frequency alternative-current magnetic susceptibility (Χ ac). The maximum value of Χ ac was reached at a thickness of 600 nm at the optimal frequency (f res) of 10 Hz, which generated maximized spin sensitivity. The resistivity (ρ) declined as the Fe2Si thickness and post-annealing temperature increased, because grain boundaries and the thin-film surface scattered the electrons. The 600 nm-thick Fe2Si thin film that was post-annealed at 250 °C had the lowest ρ of around 2.1×104 Ω · cm. The as-deposited Fe2Si thin film with a thickness of 100 nm had the highest transmittance of approximately 48%. The maximum transmittance decreased slightly as the thickness increased and upon post-annealing. The surface energy of the as-deposited Fe2Si films exceeded those of post-annealed films, revealing that the adhesion of as-deposited Fe2Si films was stronger than that of post-annealed films owing to the degree of crystallinity.

Structure and Optical, Electrical, and Adhesive Characteristics of CoFeB Thin Films.

This study investigated the structure and thermal, electrical, optical, and adhesive properties of two magnetic CoFeB thin films with compositions of Co40Fe40B20 and Co60Fe20B20.The thin films were deposited on a glass substrate by using direct current (DC) magnetron sputtering at room temperature (RT) and ranged in thicknesses from 25 to 200 Å. X-ray diffraction (XRD) patterns indicated that the thin films were amorphous. The activation energy (Q) of the Co40Fe40B20 and Co60Fe20B20 thin films exhibited concave up and concave down trends, respectively. The critical thickness of the films was 75 Å. The 75-Å-thick Co60Fe20B20 thin film exhibited the highest Q value, indicating that transforming the amorphous structure into a crystalline structure is difficult. When the Co concentration ratio was increased, the stability of the amorphous state of CoFeB increased apparently. The 75-Å-thick Co60Fe20B20 thin film exhibited the highest resistivity, whereas the 75-Å-thick Co40Fe40B20 thin film exhibited the lowest resistivity. As the thickness of the Co40Fe40B20 and Co60Fe20B20 thin films was increased, the transmittance decreased and absorbance increased. The Co60Fe20B20 thin film exhibited a higher surface energy and stronger adhesion than did the Co40Fe40B20 thin film.

Post-Annealing Effect on Magnetic, Electrical, and Adhesive Properties of FePdB Thin Films.

FePdB was sputtered on glass substrate at room temperature (RT) to thicknesses of 1000 Å, 2000 Å, 3000 Å, 4000 Å and 5000 Å with post-annealing treatment at 150 °C and 250 °C. X-ray diffraction (XRD) revealed that each FePdB thin-film yielded a significant FePd (111) crystalline peak with a 2θ of 41.17°. As the film thickness increased with the annealing temperature, the FePd (111) crystallinity became stronger. The FePd (111) texture induced the magneto crystalline anisotropy, which reduced electrical resistivity (ρ) and was associated with increased low-frequency alternative-current magnetic susceptibility (χac). The value of χac increased with the thickness and post-annealing temperature due to magneto crystalline anisotropy. The maximum value of χac was 4.2, which was obtained at a thickness of 5000 Å with post-annealing 250 °C at the optimal resonance frequency (f res) of 250 Hz, and corresponded to the highest spin sensitivity. The resistivity (ρ) fell as the FePdB thickness and post-annealing temperature increased, because the grain boundaries and the thin-film surface scattered the electrons. The 5000 Å-thick FePdB thin film that was post-annealed at 250 °C had the lowest ρ, which was approximately 246 µΩ · cm. Adhesion critically affects the surface energy of a film. The surface energies of the as-deposited FePdB films herein exceeded those of the post-annealed films, revealing that the adhesion of as-deposited FePdB films was stronger than that of post-annealed films, owing to different degrees of crystallinity. According to the χac and ρ values of the films, the 5000 Å-thick FePdB thin film that was post-annealed at 250 °C was the best suited to magnetic and electric component applications. The as-deposited 1000 Å-thick FePdB had the highest surface energy and adhesion, and can be combined with other layers in various applications.

Optical, Electrical, and Adhesive Properties of ZnO Thin Films.

ZnO films were sputtered onto glass substrates to thicknesses from 100 A to 500 A under the following conditions; (a) as-deposited films were maintained at room temperature (RT); (b) films were post-annealed at 150 °C for 1 h, and (c) films were post-annealed at 250 °C for 1 h. X-ray diffraction (XRD) result thus obtained demonstrate that ZnO has a wurtzite structure with a (002) texture diffraction peak with a 2θ of 34° range. The intensity of the ZnO (002) peak increased with film thickness and upon post-annealing. As the ZnO thin film thickness increased and post-annealing was carried out, the grains became larger. A spectral analyzer was utilized to measure transmittance for various thicknesses. Post-annealing treatment promoted the growth of grains, yielding a large mean grain size and, therefore, low transmittance. The as-deposited ZnO thin film with a thickness of 100 Å had a transmittance maximum of approximately 88% and a reflectance minimum of around 12%. Additionally, the four-point probe measurements revealed that p decreased as the ZnO thickness increased and with post-annealing treatment because grain boundaries and the surface of thin films scatter electrons, so thinner films have a greater resistance. ZnO with a thickness of 500 Å that underwent post-annealing treatment at 250 °C had a minimum resistivity of 7.6 x 10⁻³ Ω · cm. Adhesion critically influences the surface energy of films. The surface energy of as-deposited ZnO films was higher than that following post-annealing treatments, revealing that the adhesion of the as-deposited ZnO films was stronger than that following post-annealing treatment because the degree of crystallinity was lower. Accordingly, the thickness and crystallinity of ZnO importantly affects its optical, electrical, and adhesive characteristics. Finally, thinner as-deposited ZnO films exhibited better optical and adhesive properties.

Effect of Low-Frequency AC Magnetic Susceptibility and Magnetic Properties of CoFeB/MgO/CoFeB Magnetic Tunnel Junctions.

In this investigation, the low-frequency alternate-current (AC) magnetic susceptibility (χac) and hysteresis loop of various MgO thickness in CoFeB/MgO/CoFeB magnetic tunneling junction (MTJ) determined coercivity (Hc) and magnetization (Ms) and correlated that with χac maxima. The multilayer films were sputtered onto glass substrates and the thickness of intermediate barrier MgO layer was varied from 6 to 15 Å. An experiment was also performed to examine the variation of the highest χac and maximum phase angle (θmax) at the optimal resonance frequency (fres), at which the spin sensitivity is maximal. The results reveal that χac falls as the frequency increases due to the relationship between magnetization and thickness of the barrier layer. The maximum χac is at 10 Hz that is related to the maximal spin sensitivity and that this corresponds to a MgO layer of 11 Å. This result also suggests that the spin sensitivity is related to both highest χac and maximum phase angle. The corresponding maximum of χac is related to high exchange coupling. High coercivity and saturation magnetization contribute to high exchange-coupling χac strength.