Physics / Fizik
Permanent URI for this collectionhttps://hdl.handle.net/11147/6
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Article Citation - WoS: 3Citation - Scopus: 3Stable Single Layer Structures of Aluminum Oxide: Vibrational and Electronic Characterization of Magnetic Phases(Elsevier, 2022) Özyurt, A. Kutay; Molavali, Deniz; Şahin, HasanThe structural, magnetic, vibrational and electronic properties of single layer aluminum oxide (AlO2) are investigated by performing state-of-the-art first-principles calculations. Total energy optimization and phonon calculations reveal that aluminum oxide forms a distorted octahedral structure (1T′-AlO2) in its single layer limit. It is also shown that surfaces of 1T′-AlO2 display magnetic behavior originating from the O atoms. While the ferromagnetic (FM) state is the most favorable magnetic order for 1T′-AlO2, transformation to a dynamically stable antiferromagnetic (AFM) state upon a slight distortion in the crystal structure is also possible. It is also shown that Raman activities (350–400 cm−1) obtained from the vibrational spectrum can be utilized to distinguish the possible magnetic phases of the crystal structure. Electronically, both FM and the AFM phases are semiconductors with an indirect band gap and they can form a type-III vdW heterojunction with graphene-like ultra-thin materials. Moreover, it is predicted that presence of oxygen defects that inevitably occur during synthesis and production do not alter the magnetic state, even at high vacancy density. Apparently, ultra-thin 1T′-AlO2 with its stable crystal structure, semiconducting nature and robust magnetic state is a quite promising material for nanoscale device applications.Article Citation - WoS: 13Citation - Scopus: 16Synthesis and Characterization of Cationic Lipid Coated Magnetic Nanoparticles Using Multiple Emulsions as Microreactors(Elsevier Ltd., 2017) Akbaba, Hasan; Karagöz, Uğur; Selamet, Yusuf; Kantarcı, A. GültenThe aim of this study was to develop a novel iron oxide nanoparticle synthesis method with in-situ surface coating. For this purpose multiple emulsions were used as microreactors for the first time and magnetic iron oxide particles synthesized in the core of cationic solid lipid nanoparticles. DLS, SEM, TEM, VSM, Raman Spectrometer, XRD, and XPS techniques were performed for characterization of the magnetic nanoparticles. Obtained magnetic nanoparticles are superparamagnetic and no additional process was needed for surface adjustments. They are positively charged as a result of cationic lipid coating and has appropriate particle size (<30 nm) for drug or nucleic acid delivery. Structure analysis showed that magnetic core material is in the form of magnetite. Saturation magnetization value was measured as 15–17 emu g−1 for lipid coated magnetic nanoparticles obtained by multiple emulsion method which is reasonably sufficient for magnetic targeting.