Person: ALPER, MÜRSEL
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
ALPER
First Name
MÜRSEL
Name
10 results
Search Results
Now showing 1 - 10 of 10
Publication Development of electrodeposited multilayer coatings: A review of fabrication, microstructure, properties and applications(Elsevier, 2021-08-12) Aliofkhazraei, M.; Walsh, Frank C.; Zangari, Giovanni; Koçkar, Hakan; Alper, Mürsel; Rizal, Conrad; Magagnin, Luca; Protsenko, Vyacheslav; Arunachalam, Ramanathan; Rezvanian, Amirreza; Moein, Arian; Assareh, Sahar; Allahyarzadeh, Mohammad Hossein; ALPER, MÜRSEL; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; AAG-8795-2021The demand for robust engineering materials demonstrating good tribological performance under arduous service conditions has forged the development of novel coating materials and techniques. In the field of surface engineering, multilayer structures have attracted great interest. Electrodeposition offers a versatile and controlled route to engineering coatings in tribology. Electrodeposited coatings can provide tailored electronic, magnetic, mechanical, wear-resistant and corrosion-resistant characteristics as well as an improved load-bearing capability. The performance of multilayered electrodeposits can significantly exceed that of single layers. This paper critically reviews the fabrication, microstructure, engineering properties and potential applications of electrodeposited multilayer coatings. Such coatings can provide powerful, complementary additions to the toolkit for engineering electrodeposition, enabling future advances. Critical aspects requiring further R & D endeavors are identified.Publication Optimization of fe content in electrodeposited fecocu/cu magnetic multilayer(Elsevier, 2019-03-01) Koçkar, Hakan; Tekgül, Atakan; Alper, Mürsel; ALPER, MÜRSEL; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi; 0000-0001-6737-3838; 0000-0002-4862-0490; P-2124-2016; AAG-8795-2021The structural, magnetic and magnetoresistance properties of FeCoCu/Cu multilayers prepared by electrochemical deposition from a single bath containing 0.025, 0.05 and 0.1 M Fe under potentiostatic control are investigated. The deposition potentials were selected - 1.5 V for magnetic layers and - 0.4 V for non-magnetic layers concerning saturated calomel electrode. The multilayers exhibited face-centered-cubic structure in the X-ray diffraction. In the multilayer produced from the electrolyte containing 0.05 M Fe, the high saturation magnetization value (572.3 kA/m) was observed and it value drastically decreased 140.6 kA/m in the electrolyte containing 0.1 M Fe. The magnetoresistance measurements were carried out in magnetic fields in the range of +/- 955 kA/m. The high giant magnetoresistance value (18.7%) were obtained in the multilayer with 0.05 M Fe. In the magnetic sublayers of the multilayers, the more than Cu atoms deposited and due to this, the magnetoresistance curves exhibited the 2.5, 4.7, 2.4% anisotropic magnetoresistance contributions between longitudinal and transverse magnetoresistance.Publication A study on total thickness dependency: Microstructural, magnetoresistance and magnetic properties of electrochemically deposited permalloy based multilayers(Springer, 2015-07-01) Kuru, Hilal; Koçkar, Hakan; Alper, Mürsel; ALPER, MÜRSEL; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü; AAG-8795-2021Electrochemically deposited permalloy based NiFe/Cu multilayers, relating their magnetic and magnetoresistance properties with crystal structure and the corresponding film composition were studied as a function of the total film thickness. The permalloy based multilayers were grown on strong (110) textured copper sheets with electrodeposition under potentiostatic control. The total multilayer film thickness was changed from 0.3 to 5 mu m while ferromagnetic nickel-iron and nonmagnetic copper layer thickness was kept constant at 3 and 1 nm, respectively. Energy dispersive X-ray analysis revealed that the nickel and iron content of the multilayers decreased and copper content increased as the total film thickness increased. All multilayers exhibited face-centred cubic structure with (110) preferred orientation. The highest peak intensity changed from (220) to (111) when the total thickness was higher than 2 mu m. The multilayers exhibited giant magnetoresistance (GMR). The maximum GMR magnitude of similar to 4 % was obtained for the films with total thickness less than 1 mu m and the GMR decreased down to similar to 1 % with increasing film thickness to 5 mu m. The saturation magnetisation and coercivity decreased from 78 to 11 emu/cm 3 and from 24 to 12 Oe as the total thickness of the multilayers increased from 0.3 to 5 mu m, respectively. The variations in magnetic and magnetoresistive properties related to the microstructure were attributed to the variation of the film contents caused by total film thickness.Publication Relation between ferromagnetic layer thickness (NiCu) and properties of NiCu/Cu multilayers (vol 26, pg 5014, 2015)(Springer, 2015-07-01) Kuru, Hilal; Koçkar, Hakan; Alper, Mürsel; Hacıismailoğlu, Mürşide; ALPER, MÜRSEL; ŞAFAK HACIİSMAİLOĞLU, MÜRŞİDE; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0001-5648-3230; AAH-9719-2021; AAG-8795-2021Publication Structural, magnetic and GMR properties of FeCo(Cu)/Cu magnetic multilayers electrodeposited at high cathode potentials of the magnetic layer(Natl Inst Optoelectronics, 2020-03-01) Tekgül, Atakan; Şahin, T.; Koçkar, H.; Alper, Mürsel; Tekgül, Atakan; ALPER, MÜRSEL; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü; 0000-0001-6737-3838; AAG-8795-2021; P-2124-2016Structural, magnetic and giant magnetoresistance properties of the electrochemically deposited FeCo(Cu)/Cu multilayers at the various cathode potentials for magnetic layers were investigated. The cathode potentials were -1.8, -2.0, -2.5 and -2.8 V for magnetic layers and -0.3 V for non-magnetic layers with respect to a saturated calomel electrode. The multilayers have a face-centred-cubic structure. The obtained composition was found to be close the nominal composition at -2.8 V cathode potential. The highest giant magnetoresistance value (16.50 %) was obtained in the multilayer produced at -1.8 V. The highest sensitivity was found in the multilayer produced at -1.8 and -2.8 V.Publication Change in planar hall effect ratio of Ni-Co films produced by electrodeposition(Elsevier, 2015-01-01) Karpuz, Ali; Koçkar, Hakan; Alper, Mürsel; ALPER, MÜRSEL; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; AAG-8795-2021Ni-Co Films were produced by the electrodeposition technique and their magnetotransport properties were studied. The anisotropic magnetoresistance (AMR) and the planar Hall effect (PRE) ratios were Found using the van der Pauw setup at room temperature. It was observed that the ORE ratios were larger than the obtained AMR ratios. While the maximum changes in longitudinal and transversal magnetoresistance ratios were 6.8% and 140%, respectively, the change in ORE values was up to 500%. In the ORE measurements, the magnetoresistance orientation depends on the electrical resistance values which occur in branches of the films.Publication Electrodeposited CoFeCu films at high and low ph levels: Structural and magnetic properties(Springer, 2015-04-01) Koçkar, Hakan; Özergin, Ercüment; Karaağaç, Öznur; Alper, Mürsel; Kuru, Hilal; Hacıismailoğlu, Mürside; ALPER, MÜRSEL; ŞAFAK HACIİSMAİLOĞLU, MÜRŞİDE; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0001-5648-3230; AAH-9719-2021; AAG-8795-2021CoFeCu films were electrodeposited at high and low pH, and their structural, magnetic and magnetoresistance properties were studied. Current-time transients were recorded to observe the proper deposition of the films. Crystal structure was displayed with X-ray diffraction. All films had a face centered cubic structure and the crystal structure was dominated by fcc-Co. The morphology and elemental composition of the films were determined by scanning electron microscope and energy dispersive X-ray spectroscopy, respectively. The surface of the film deposited at low pH has larger roundish shapes than that of the film deposited at high pH. The saturation magnetization increases from 1,210 to 1,413 emu/cm(3) and coercivity increases from 29 to 39 Oe as the electrolyte pH increases. All CoFeCu films showed anisotropic magnetoresistance. It is seen that electrolyte pH has an substantial affect on the morphological and magnetic properties of the films.Publication Characterizations of electrodeposited NiCoFe ternary alloys: Influence of deposition potential(Springer, 2015-06-01) Kuru, Hilal; Koçkar, Hakan; Demirbaş, Özen; Alper, Mürsel; ALPER, MÜRSEL; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; AAG-8795-2021Microstructural, magnetoresistance and magnetic properties of electrodeposited NiCoFe ternary alloys were investigated in terms of deposition potentials changing from -1.8 to -3.0 V with respect to saturated calomel electrode. The alloys were grown on polycrystalline Titanium substrates. The potentials were obtained from cyclic voltammetry and the current-time transients were also recorded to control the growth of proper alloys. From the structural analysis by X-ray diffraction, all alloys had a face-centred cubic structure. The alloy compositions by energy dispersive X-ray spectroscopy revealed that the Ni content increases whereas the Co and Fe contents decrease as the deposition potential increase. And, the scanning electron microscope images disclosed that the alloy morphologies changed as the deposition potential changed. All alloys showed anisotropic magnetic resistance and their magnitudes were between 4.5 and 8.7 %. The vibrating sample magnetometer measurements showed that the saturation magnetization of the alloys increases from 748 to 786 emu/cm(3) and coercivity decreases from 28.7 to 25.9 Oe as the deposition potential increases. The easy axis of magnetization was found to be parallel to the film plane for all alloys. The variations in magnetic and magnetoresistive properties related to the microstructure were attributed to the compositional changes caused by the deposition potential.Publication Effect of l-ascorbic acid on electrochemically deposited fecocu/cu magnetic multilayer granular films: Structural, magnetic and magnetoresistance properties(Elsevier, 2020-09-01) Şahin, Turgut; Koçkar, Hakan; ALPER, MÜRSEL; Tekgül, Atakan; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0001-6737-3838; 0000-0002-4862-0490; AAG-8795-2021; P-2124-2016The FeCoCu/Cu multilayer granular films were prepared by the electrochemical deposition technique, and the effect of the L-ascorbic acid molarity on their structural, magnetic, and magnetoresistance properties was investigated. The structure of multilayer granular films is a face-centered cubic at room temperature, and the crystallite size increases from 5 to 14 nm with increasing the molarity of the L-ascorbic acid in the electrolyte. The recorded current-time curves indicate that 0.06 M L-ascorbic acid causes high current (200 mA) in the deposition of the magnetic layer during the electrochemical deposition process. The compositional analysis indicates that Fe deposition amount increases with increasing the L-ascorbic acid for the 0.04 and 0.06 M. The saturation magnetization decreases in the thin films due to increasing the molarity of L-ascorbic acid in the electrolyte. However, some of the Co and Fe reduces as a form of their oxide in the multilayer granular films containing a high amount of magnetic materials, and the antiferromagnetic behavior suppresses the ferromagnetic behavior. The multilayer granular film produced from the electrolyte with 0.04 M L-ascorbic acid exhibits both high magnetoresistance as 12% and 3.5% anisotropic magnetoresistance effect, and also, about 1 nm particle size.Publication Effect of mn doping on structural, optical and magnetic properties of zno films fabricated by sol-gel spin coating method(Springer, 2023-02-01) GÜLTEKİN, ZAFER; ALPER, MÜRSEL; Akay, Cengiz; AKAY, CENGİZ; Hacıismailoğlu, M. Cüneyt; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-0781-3376; 0000-0002-8037-0364; K-7950-2012; W-1656-2017We have fabricated undoped ZnO and Mn-doped ZnO thin films on glass substrates using sol-gel spin coating method and investigated their structural, optical, magnetic and magnetoresistance properties depending on the Mn doping ratio. X-ray diffraction (XRD) patterns showed that all the films under study are predominantly crystalized in a single-phase wurtzite structure. Scanning electron microscope (SEM) images revealed that the films become more homogeneous, continuous and pinhole-free coatings as the Mn content of the films increases. Optical characterizations by UV-visible spectrometer indicated that transmittance spectra of all films have a high transmittance above 85% in visible region, while they show the absorbance spectra in 300-400 nm range. In addition, it was observed that the optical energy band edges shift to red with increasing Mn content, due to probably increasing the carrier concentration. The refractive index and the dielectric constant are also affect by the Mn content. Magnetic measurements by vibrating sample magnetometer showed that the film magnetic properties change from diamagnetic to ferromagnetic as the Mn content increases. Furthermore, it was found that the magnetoresistance measurements support their magnetic behavior of the films.