Browsing by Author "Lonescu, M"

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    Polarized neutron reflectometry of epitaxial Fe[0.25 + x] Pt[0.75 – x] layers.
    (Institute of Electrical and Electronics Engineers (IEEE), 2018-04-27) Mankey, GJ; Causer, GL; Cortie, DL; Wang, X; Zhu, H; Lonescu, M; Klose, F
    Epitaxial Fe[0.25 + x]Pt[0.75 - x] layers can be either antiferromagnetic (AF) or ferromagnetic (FM) depending on the degree of chemical ordering controlled by the deposition temperature. Our neutron diffraction studies were the first to study AF phase transitions in these thin films [1] and we have also shown using PNR that a mixed AF-FM film is exchange biased with itself [2]. In AF-FM exchange-biased superlattices with a modulated chemical order parameter, PNR shows the magnetization can be modulated through the film thickness with no composition modulations [3]. Our recent results reveal that He+ ion bombardment and annealing can be applied toward controlling magnetic phases in epitaxial Fe [0.25] Pt [0.75] layers [4]. © Copyright 2024 IEEE - All rights reserved, including rights for text and data mining and training of artificial intelligence and similar technologies.
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    X-ray absorption spectroscopy at the Ni-K edge in stackhousia tryonii bailey hyperaccumulator
    (Wiley-Blackwell, 2008-11) Lonescu, M; Bhatia, NP; Cohen, DD; Kachenko, AG; Siegele, R; Marcus, MA; Fakra, SC; Foran, GJ
    Young plants of Stackhousia tryonii Bailey were exposed to 34 mM Ni kg(-1) in the form of NiSO4 center dot 6H(2)O solution and grown under controlled glasshouse conditions fora period of 20 days. Fresh leaf, stem and root samples were analysed in vivo by micro x-ray absorption spectroscopy (XAS) at the Ni-K edge. Both x-ray absorption near edge structure and extended x-ray absorption fine structure spectra were analysed, and the resulting spectra were compared with spectra obtained from nine biologically important Ni-containing model compounds. The results revealed that the majority of leaf, stem and root Ni in the hyperaccumulator was chelated by citrate. Our results also suggest that in leaves Ni is complexed by phosphate and histidine, and in stems and roots, phytate and histidine. The XAS results provide an important physiological insight into transport, detoxification and storage of Ni in S. tryonii plants. © 2008, Wiley-Blackwell.