Amir Sayid Hassan Rozatian

University of Isfahan

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B. K. Tanner

Durham University

T. P. A. Hase

University of Warwick

Ghahraman Solookinejad

Islamic Azad University, Marvdasht

Mohammad Yousefi

Islamic Azad University, Tehran

M.H. Habibi

Université Ibn-Tofail

Esmail Kiani

Malek Ashtar University of Technology

B. D. Fulthorpe

Durham University

C. H. Marrows

University of Leeds

Mohammadamin Emami

University of Isfahan

Manijeh Hadian Dehkordi

National Research Institute of Cultural Heritage

Cooperative Institutions

University of Isfahan

Durham University

University of Leeds

European Synchrotron Radiation Facility

Centre National de la Recherche Scientifique

National Physical Laboratory

Institut de Recherche sur les ArchéoMATériaux

Malek Ashtar University of Technology

Islamic Azad University, Tehran

Shahid Beheshti University

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Anisotropy and interface structure in magnetic multilayers

Amir Sayid Hassan Rozatian

It is believed that the interfacial structure can significantly affect the magnetic properties of magnetic multilayer thin films. X-ray scattering techniques provide a powerful method with which to study the bulk and interface morphology in these systems, and are therefore crucial in developing an understanding of the dominant factors influencing the magnitude of the perpendicular magnetic anisotropy (PMA).The inter-relation between magnetic and structural properties of a series of magnetic multilayer thin films is investigated. Magnetometry measurements on a series of Fe/Au multilayers showed that some samples exhibited in-plane magnetization. X-ray data and simulations showed that the interface roughness was high in these samples. However, the formation and propagation of uncorrelated roughness followed a systematic trend for surface growth. On the other hand, x-ray data and simulations for a single 100-bilayer sample showed that the interfaces are much better defined with significantly lower roughness. This was the only sample to show perpendicular anisotropy supposing the suggestion that the absence of PMA in all other samples is associated with high interface roughness. Magnetometry measurements of the PMA in Co/Pt multilayers show an increase in effective anisotropy at about 15 bilayers. X-ray data showed that the roughness of the interfaces was correlated in all samples and that the interfaces were sharp with no detectable interdiffusion. No systematic trend in roughness or crystallographic texture is detected with increasing bilayer repeat X-ray measurements on four series of Co/Pd multilayers show interface roughness independent of bilayer repeat number. For Co/Pt, the in-plane correlation length was independent of bilayer number while for Co/Pd and Fe/Au it increased. A saturation of the in-plane correlation length for the Au/Fe system where island growth of the Au occurs was observed. The out-of-plane correlation length increased with bilayer repeat for Co/Pt and Co/Pd. The interfaces in samples with higher PMA had a fractal parameter close to unity.

Texture (cosmology)

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INVESTIGATION OF SOL-GEL GROWN ZnO THIN FILM: WAVELET ANALYSIS AND SIMULATED ANNEALING OPTIMIZED X-RAY REFLECTIVITY

International Journal of Modern Physics B (2012)

Ghahraman Solookinejad Amir Sayid Hassan Rozatian M.H. Habibi

In this study ZnO thin film was fabricated by sol-gel spin coating method on glass substrate. X-ray reflectivity (XRR) and its optimization by simulated annealing (SA) technique have been used for characterization and extracting physical parameters of the film. The model independent information was needed to establish data analyzing process for XRR before optimization process. This independent information was extracted from wavelet transform of Fresnel reflectivity normalized XRR. This transformation yields thickness of each coated layer. This information was a keynote for constructing optimization process. Specular XRR optimization yielded structural parameters such as thickness, roughness of surface and interface and electron density profile of the film. Acceptable agreement exists between results obtained from wavelet transformation and XRR fitting.

X-ray reflectivity

10.1142/s0217979212500701

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Citations (4)

Simulation of ultrasoft X-rays induced DNA damage using the Geant4 Monte Carlo toolkit

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms (2014)

Marjan Tajik Amir Sayid Hassan Rozatian Farid Semsarha

10.1016/j.nimb.2014.10.023

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Surface characterization and microstructure of ITO thin films at different annealing temperatures

Applied Surface Science (2007)

Davood Raoufi Ahmad Kiasatpour Hamidreza Fallah Amir Sayid Hassan Rozatian

Indium tin oxide

10.1016/j.apsusc.2007.05.032

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Citations (211)

Optical study of narrow band gapInAsxSb1−x(x=0, 0.25, 0.5, 0.75, 1) alloys

Physical Review B (2015)

Shirin Namjoo Amir Sayid Hassan Rozatian Iraj Jabbari Peter Puschnig

The structural, electronic, and optical properties of InAs, InSb, and their ternary alloys ${\mathrm{InAs}}_{x}{\mathrm{Sb}}_{1\ensuremath{-}x}$ ($x=0.25$, 0.5, 0.75) are investigated within density functional theory utilizing the wien2k package. We find that the lattice constants and bulk moduli as a function of $x$ are in best agreement with Vegard's linear rule. When computing the electronic band structures with the modified Becke-Johnson exchange-correlation functional (mBJLDA), our results for the band gaps of InAs, InSb, and their ternary alloys are in good agreement with the available experimental results while the conventional Wu-Cohen generalized gradient approximation (GGA) functional leads to zero or close to zero band gaps. In particular, our mBJLDA results confirm experimental evidence that the minimum band gap occurs for As concentrations around $x\ensuremath{\approx}0.3$. Furthermore, we investigate the dielectric function of these compounds within the random phase approximation using both the Wu-Cohen GGA and the mBJLDA functionals. While the mBJLDA results of our fully first-principles calculations show good agreement of the peak positions in ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$ with experiments, the peaks in the optical spectra based on the Wu-Cohen GGA band structure appear redshifted compared to experiment. We further identify the interband transitions responsible for the structures in the spectra. Looking at the optical matrix element, we note that the major peaks are dominated by transition from the Sb $5p$ (As $4p$) states to In $s$ states for InSb and ${\mathrm{InAs}}_{0.25}{\mathrm{Sb}}_{0.75}$ (InAs, ${\mathrm{InAs}}_{0.75}{\mathrm{Sb}}_{0.25}$, and ${\mathrm{InAs}}_{0.5}{\mathrm{Sb}}_{0.5}$).

10.1103/physrevb.91.205205

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ChemInform Abstract: X‐Ray Probes of Magnetic Multilayer Structure

ChemInform (2001)

B. K. Tanner T. P. A. Hase B. D. Fulthorpe John Clarke Guangming Luo

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

10.1002/chin.200137251

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Influence of lattice expansion on the topological band order of InAsxSb1−x (x=0, 0.25, 0.5, 0.75, 1) alloys

Journal of Alloys and Compounds (2014)

Shirin Namjoo Amir Sayid Hassan Rozatian Iraj Jabbari

Tetragonal crystal system

Lattice constant

Lattice (music)

10.1016/j.jallcom.2014.12.131

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The out-of-plane correlation length of the conformal roughness in Co–Pd multilayers

Physica B Condensed Matter (2004)

A. T. G. Pym Amir Sayid Hassan Rozatian C. H. Marrows B. J. Hickey T. P. A. Hase

Length scale

10.1016/j.physb.2004.11.050

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Citations (2)

Unravelling Mummy's Fashion: Synchrotron Ftir Microspectroscopy for Characterization of Natural Dyes Used in the Textile of Saltman's Trouser from Chehrabad Salt Mine in Zanjan-Iran (220-390 A.D.)

Manijeh Hadian Dehkordi Gihan Kamel Amir Sayid Hassan Rozatian Farah Sadat Madani Sahar Nouhi

In 1993, salt miners stumbled upon an unexpected treasure while extracting salt from the mines—a half-preserved body with long hair and a beard. Further archaeological investigations revealed that these remarkable mummies, known as the Saltmen, belonged to miners spanning the Achaemenid period to the Islamic era. The focus turned to the unique short trousers worn by Saltman No. 1, dating back to A.D. 220-390 during the Sasanian Empire. These trousers were crafted from wool fibers adorned with vibrant patterns in red, blue, green-yellow, and brown. To uncover the secrets of these ancient dyes, synchrotron FTIR microspectroscopy technique was employed. Meticulous analysis identified several natural materials as potential sources for the colorful dyes: Indigotin (Indigo): Responsible for the rich blue hue, Tannic Acid (Tannin): Contributed to brown tones, Quercetin and Apigenin (Flavonoids): Associated with green-yellow shades, and Alizarin and Carminic Acid (Anthraquinones): Used for red coloring. Additionally, the study demonstrated that combining SR-based techniques with multivariate statistical analysis and second derivative spectra allowed for better identification of ancient dyed fibers, even with minimal samples. These findings provide a captivating glimpse into the craftsmanship and artistic sensibilities of the Sassanid era.

Anthraquinones

Treasure

Textile

10.2139/ssrn.4834488

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The progression of interface structure through sputtered Co/Cu and Co/Pt multilayer films

Journal of Physics Condensed Matter (1999)

B. D. Fulthorpe D. E. Joyce T. P. A. Hase Amir Sayid Hassan Rozatian B. K. Tanner

The progression of interface structure through some Co/Cu and Co/Pt multilayer systems, grown on silicon and glass substrates respectively, has been studied using grazing incidence x-ray scattering. Simulations of the data shows that the interface characteristics of the Co/Cu system propagate unchanged with increasing numbers of bilayers. The interface roughness, lateral length scale and fractal dimension remain constant across the series of samples. In contrast, a reduction in the interface conformality between top and bottom surfaces with respect to increasing numbers of bilayers is observed in the Co/Pt system; however the roughness correlation between successive layers is largely maintained. Magnetization data for Co/Cu indicate that the Co layer immediately adjacent to the substrate is magnetically `dead'. This could result from mixing of the cobalt and silicon oxide species at the substrate interface.

Silicon oxide

10.1088/0953-8984/11/43/310

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Citations (15)