İlknur GÜNDÜZ AYKAÇ, Aykut Can Önel, Burcu TOYDEMİR YAŞASUN, L. ÇOLAKEROL ARSLAN
We investigated the effects of crystalline order on the structural and magnetic properties of ultrathin Mndoped Ge thin films grown by thermal diffusion. The dopant motion which occurs during the annealing stage appears to differ considerably depending upon whether the Ge layer is in a crystalline or an amorphous state. The details of the temperature-dependent magnetization curves reveal that the a-MnGe and c-MnGe films show ferromagnetic property up to 300K and ~250K, respectively. Ferromagnetic Mn5 Ge3 thin film with weakly anisotropic in-plane magnetization is formed on amorphous Ge thin film, while weakly ferromagnetic Mn5 Gex Si3−x nanostructures are developed on crystalline Ge thin film due to diffusion of Mn atoms through the Ge layer and interact with Si substrate.
{"title":"Magnetic properties of Mn doped crystalline and amorphous Ge thin films grown on Si (111)","authors":"İlknur GÜNDÜZ AYKAÇ, Aykut Can Önel, Burcu TOYDEMİR YAŞASUN, L. ÇOLAKEROL ARSLAN","doi":"10.3906/fiz-1909-17","DOIUrl":"https://doi.org/10.3906/fiz-1909-17","url":null,"abstract":"We investigated the effects of crystalline order on the structural and magnetic properties of ultrathin Mndoped Ge thin films grown by thermal diffusion. The dopant motion which occurs during the annealing stage appears to differ considerably depending upon whether the Ge layer is in a crystalline or an amorphous state. The details of the temperature-dependent magnetization curves reveal that the a-MnGe and c-MnGe films show ferromagnetic property up to 300K and ~250K, respectively. Ferromagnetic Mn5 Ge3 thin film with weakly anisotropic in-plane magnetization is formed on amorphous Ge thin film, while weakly ferromagnetic Mn5 Gex Si3−x nanostructures are developed on crystalline Ge thin film due to diffusion of Mn atoms through the Ge layer and interact with Si substrate.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":"44 1","pages":"67-76"},"PeriodicalIF":2.1,"publicationDate":"2020-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48671624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cladding light strippers are essential components in high-power fiber lasers used for removal of unwanted cladding light that can distort the beam quality or even damage the whole fiber laser system. In this study, an Atomic Layer Deposition system was used for the first time to prepare the cladding light stripper devices using a 40 nm thick zirconia layer grown on optical fiber. The thickness of the zirconia coating was confirmed using the Scanning Electron Microscopy (SEM) and the Ellipsometry techniques. The elemental analysis was also performed using the wavelength dispersive X-ray spectroscopy technique. The Raman spectroscopy and XRD data confirm the structure of the atomic layer deposition-grown zirconia thin films to be predominantly amorphous. The cladding light stripper devices formed using the zirconia thin films with the lengths of 8.5 and 15.5 cm were able to strip approximately 30% (~1.5 dB) and 40% (~2.3 dB) of the unwanted cladding light.
{"title":"Atomic layer deposition of zirconium oxide thin film on an optical fiber for cladding light strippers","authors":"A. Karatutlu","doi":"10.3906/fiz-1908-6","DOIUrl":"https://doi.org/10.3906/fiz-1908-6","url":null,"abstract":"Cladding light strippers are essential components in high-power fiber lasers used for removal of unwanted cladding light that can distort the beam quality or even damage the whole fiber laser system. In this study, an Atomic Layer Deposition system was used for the first time to prepare the cladding light stripper devices using a 40 nm thick zirconia layer grown on optical fiber. The thickness of the zirconia coating was confirmed using the Scanning Electron Microscopy (SEM) and the Ellipsometry techniques. The elemental analysis was also performed using the wavelength dispersive X-ray spectroscopy technique. The Raman spectroscopy and XRD data confirm the structure of the atomic layer deposition-grown zirconia thin films to be predominantly amorphous. The cladding light stripper devices formed using the zirconia thin films with the lengths of 8.5 and 15.5 cm were able to strip approximately 30% (~1.5 dB) and 40% (~2.3 dB) of the unwanted cladding light.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":"44 1","pages":"49-56"},"PeriodicalIF":2.1,"publicationDate":"2020-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3906/fiz-1908-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47750167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analysis of chaotic and regular behavior of Matinyan–Yang–Mills–Higgs Hamiltonian system","authors":"Engin Kandıran, A. Hacinliyan","doi":"10.3906/fiz-1906-20","DOIUrl":"https://doi.org/10.3906/fiz-1906-20","url":null,"abstract":"","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":"44 1","pages":"1-9"},"PeriodicalIF":2.1,"publicationDate":"2020-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46151168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The magnetoresistive NiFe/Pt sensor was fabricated by using standard microlithography and sputter deposition techniques and then the magnetic and magnetotransport properties were investigated. The magnetic properties of the sample show that the easy axis of magnetization prefers a predefined direction along the Hall bar. Moreover, the sample has uniaxial magnetic anisotropy due to the growth-induced magnetic anisotropy. On the other hand, the Anisotropic magnetoresistance (AMR) and the Planar Hall effect (PHE) of the sample were investigated in detail between 0°and 360°. The angle-dependent AMR and PHE signals at the in-plane magnetic field of constant magnitude intersect at certain angles. At these angles, the presence of unusual peaks and valleys was observed. This is proof that AMR and PHE curves had strongly affected each other at certain angles.
{"title":"Anisotropic magnetoresistance and planar Hall effect in magnetoresistive NiFe/Pt thin film","authors":"E. Demirci","doi":"10.3906/fiz-1910-15","DOIUrl":"https://doi.org/10.3906/fiz-1910-15","url":null,"abstract":"The magnetoresistive NiFe/Pt sensor was fabricated by using standard microlithography and sputter deposition techniques and then the magnetic and magnetotransport properties were investigated. The magnetic properties of the sample show that the easy axis of magnetization prefers a predefined direction along the Hall bar. Moreover, the sample has uniaxial magnetic anisotropy due to the growth-induced magnetic anisotropy. On the other hand, the Anisotropic magnetoresistance (AMR) and the Planar Hall effect (PHE) of the sample were investigated in detail between 0°and 360°. The angle-dependent AMR and PHE signals at the in-plane magnetic field of constant magnitude intersect at certain angles. At these angles, the presence of unusual peaks and valleys was observed. This is proof that AMR and PHE curves had strongly affected each other at certain angles.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":"44 1","pages":"77-84"},"PeriodicalIF":2.1,"publicationDate":"2020-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3906/fiz-1910-15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48859531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Quantum oscillation phenomena in narrow-gap semiconductors at different temperatures","authors":"","doi":"10.3906/fiz-1911-10","DOIUrl":"https://doi.org/10.3906/fiz-1911-10","url":null,"abstract":"","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70203369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Wetzel, E. Tiras, B. Bilki, N. Bostan, O. K. Köseyan
The timing characteristics of scintillators must be understood in order to determine which applications theyare appropriate for. Polyethylene naphthalate (PEN) and polyethylene teraphthalate (PET) are common plastics withuncommon scintillation properties. Here, we report the timing characteristics of PEN and PET, determined by excitingthem with 120 GeV protons. The test beam was provided by Fermi National Accelerator Laboratory, and the scintillatorswere tested at the Fermilab Test Beam Facility. PEN and PET are found to have dominant decay constants of 34.91 nsand 6.78 ns, respectively.
{"title":"Scintillation timing characteristics of common plastics for radiation detectionexcited with 120 GeV protons","authors":"J. Wetzel, E. Tiras, B. Bilki, N. Bostan, O. K. Köseyan","doi":"10.3906/fiz-1912-9","DOIUrl":"https://doi.org/10.3906/fiz-1912-9","url":null,"abstract":"The timing characteristics of scintillators must be understood in order to determine which applications theyare appropriate for. Polyethylene naphthalate (PEN) and polyethylene teraphthalate (PET) are common plastics withuncommon scintillation properties. Here, we report the timing characteristics of PEN and PET, determined by excitingthem with 120 GeV protons. The test beam was provided by Fermi National Accelerator Laboratory, and the scintillatorswere tested at the Fermilab Test Beam Facility. PEN and PET are found to have dominant decay constants of 34.91 nsand 6.78 ns, respectively.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2019-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49417691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Didem Ketenoglu, E. Bostanci, A. Aydin, B. Ketenoglu
Accelerator-based fourth-generation light sources are utilized in a wide range of interdisciplinary applications such as nanotechnology, materials science, biosciences, and medicine. A hard X-ray free-electron laser (FEL), as a state-of-the-art light source, was optimized using evolutionary algorithms for dedicated user applications such as X-ray Raman scattering (XRS), resonant inelastic X-ray scattering (RIXS), and X-ray emission spectroscopies (XES). Optimal parameter sets were obtained for an in-vacuum planar undulator driven by an 8 GeV electron beam. Performance parameters of self-amplified spontaneous emission (SASE) operation (i.e. optimized SASE performance parameters through evolutionary algorithms) were found to be consistent with operating X-ray FEL facilities around the world. It is shown that FEL characteristics for specific user experiments can be optimized by finding several evolutionary algorithm solutions within the range of 5 keV to 10 keV.
{"title":"A hard X-ray self-amplified spontaneous emission free-electron laser optimizationusing evolutionary algorithms for dedicated user applications","authors":"Didem Ketenoglu, E. Bostanci, A. Aydin, B. Ketenoglu","doi":"10.3906/fiz-1909-5","DOIUrl":"https://doi.org/10.3906/fiz-1909-5","url":null,"abstract":"Accelerator-based fourth-generation light sources are utilized in a wide range of interdisciplinary applications such as nanotechnology, materials science, biosciences, and medicine. A hard X-ray free-electron laser (FEL), as a state-of-the-art light source, was optimized using evolutionary algorithms for dedicated user applications such as X-ray Raman scattering (XRS), resonant inelastic X-ray scattering (RIXS), and X-ray emission spectroscopies (XES). Optimal parameter sets were obtained for an in-vacuum planar undulator driven by an 8 GeV electron beam. Performance parameters of self-amplified spontaneous emission (SASE) operation (i.e. optimized SASE performance parameters through evolutionary algorithms) were found to be consistent with operating X-ray FEL facilities around the world. It is shown that FEL characteristics for specific user experiments can be optimized by finding several evolutionary algorithm solutions within the range of 5 keV to 10 keV.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":"43 1","pages":"551-555"},"PeriodicalIF":2.1,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43768243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We show that $p$-form fields can go through spontaneous growth due to various couplings in gravity theories, forming a new example of spontaneous tensorization. Generalizing the spontaneous scalarization theory of Damour and Esposito-Farese where the original idea has been applied to different fields from vectors to spinors has received high levels of interest in recent years. We first review this existing literature on spontaneous growth in gravity, and then apply the known mechanisms to $p$-forms. We show that one can induce spontaneous growth in $p$-forms for each of the regularized instability mechanisms, which was not the case for other types of fields. We obtain theories with the common property that they lead to large deviations from general relativity in strong gravity as is usual in spontaneous tensorization. This is especially interesting for gravitational wave observations, a direct probe of this regime.
{"title":"Various paths to the spontaneous growth ofp-form fields","authors":"Fethi M. Ramazanoğlu","doi":"10.3906/fiz-1908-8","DOIUrl":"https://doi.org/10.3906/fiz-1908-8","url":null,"abstract":"We show that $p$-form fields can go through spontaneous growth due to various couplings in gravity theories, forming a new example of spontaneous tensorization. Generalizing the spontaneous scalarization theory of Damour and Esposito-Farese where the original idea has been applied to different fields from vectors to spinors has received high levels of interest in recent years. We first review this existing literature on spontaneous growth in gravity, and then apply the known mechanisms to $p$-forms. We show that one can induce spontaneous growth in $p$-forms for each of the regularized instability mechanisms, which was not the case for other types of fields. We obtain theories with the common property that they lead to large deviations from general relativity in strong gravity as is usual in spontaneous tensorization. This is especially interesting for gravitational wave observations, a direct probe of this regime.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44316846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Doğanci, Ş. Kaya, A. Aktağ, Elif SARIGÜL DUMAN, R. Turan, H. Karacali, E. Yılmaz
In this work, characteristics of silicon-based p$^{+, }$type, intrinsic (I), n$^{-}$ type (Si-PIN) photodiodes with active area of 3.5 $times $ 3.5 mm$^{2}$, 5.0 $times $ 5.0 mm$^{2}$, or 7.0 $times $ 7.0 mm$^{2}$ and their possible usage in optoelectronics were studied. The devices were fabricated in the Radiation Detector Application and Research Center (NURDAM) of Bolu Abant Izzet Baysal University, Turkey. To acquire the device specifications, the current-voltage (I-V) and the capacitance-voltage (C-V) measurements were carried out in the photoconductive mode. Quantum efficiency and spectral responsivity measurements were performed in the photovoltaic mode. Both measurements were carried out in a dark environment at room temperature. The measured values of the dark current (I$_{dc})$ and the capacitance of photodiodes were -6.97 to -19.10 nA and 23 to 61 pF at -5 V, respectively. The quantum efficiency measurements of the devices increased up to 66%. P responsivity was found to be 0.436 $pm $ 1 mA/W at 820 nm. The results indicate that the I$_{dc}$ current and the performance of the devices were improved. Therefore, the devices can be utilized for optoelectronics applications and commercial usage.
{"title":"Fabrication and characterization of Si-PIN photodiodes","authors":"E. Doğanci, Ş. Kaya, A. Aktağ, Elif SARIGÜL DUMAN, R. Turan, H. Karacali, E. Yılmaz","doi":"10.3906/fiz-1905-16","DOIUrl":"https://doi.org/10.3906/fiz-1905-16","url":null,"abstract":"In this work, characteristics of silicon-based p$^{+, }$type, intrinsic (I), n$^{-}$ type (Si-PIN) photodiodes with active area of 3.5 $times $ 3.5 mm$^{2}$, 5.0 $times $ 5.0 mm$^{2}$, or 7.0 $times $ 7.0 mm$^{2}$ and their possible usage in optoelectronics were studied. The devices were fabricated in the Radiation Detector Application and Research Center (NURDAM) of Bolu Abant Izzet Baysal University, Turkey. To acquire the device specifications, the current-voltage (I-V) and the capacitance-voltage (C-V) measurements were carried out in the photoconductive mode. Quantum efficiency and spectral responsivity measurements were performed in the photovoltaic mode. Both measurements were carried out in a dark environment at room temperature. The measured values of the dark current (I$_{dc})$ and the capacitance of photodiodes were -6.97 to -19.10 nA and 23 to 61 pF at -5 V, respectively. The quantum efficiency measurements of the devices increased up to 66%. P responsivity was found to be 0.436 $pm $ 1 mA/W at 820 nm. The results indicate that the I$_{dc}$ current and the performance of the devices were improved. Therefore, the devices can be utilized for optoelectronics applications and commercial usage.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":"43 1","pages":"556-562"},"PeriodicalIF":2.1,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3906/fiz-1905-16","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41800678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article discusses the possible place and role of the well-known thermodynamic Joule-Thomson effect in the technology of capillary-porous materials. The presence of the Joule-Thomson effect in these materials is substantiated by the peculiarities of the mechanism and kinetics of the diffusion physicochemical processes proceeding when they are heated. A mathematical description of the integral effects in capillary-porous materials under isothermal conditions is given.
{"title":"On possible inversion effects in the technology of capillary-porous materials","authors":"B. Yerzhenbek","doi":"10.3906/fiz-1903-10","DOIUrl":"https://doi.org/10.3906/fiz-1903-10","url":null,"abstract":"The article discusses the possible place and role of the well-known thermodynamic Joule-Thomson effect in the technology of capillary-porous materials. The presence of the Joule-Thomson effect in these materials is substantiated by the peculiarities of the mechanism and kinetics of the diffusion physicochemical processes proceeding when they are heated. A mathematical description of the integral effects in capillary-porous materials under isothermal conditions is given.","PeriodicalId":46003,"journal":{"name":"Turkish Journal of Physics","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47630721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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