title: Magnetic States in Ensemble of Ferromagnetic Nanoparticles in Cu-Mn-Al Alloy.
abstract: Two Cu-Mn-Al samples of different compositions were studied: one exhibiting martensitic transformation, another without structural transition. X-ray diffraction and magnetic measurements demonstrate that different magnetic behaviors of alloys originate from different concentrations and sizes of ferromagnetic nanoparticles, which appear after solid solution decomposition.Estimation of magnetic moments of ferromagnetic nanoparticles from magnetization curves was performed using Langevin function and compared to those obtained from X-ray examination. Granular systems are known to show giant magnetoresistance. Therefore, magnetoresistance of Cu-Mn-Al melt-spun ribbons after different aging times was measured. The study has shown that increase in the concentration of Mn atoms and time of aging in Cu-Mn-Al alloy leads to an increase in the amount of precipitated phase appearing as ferromagnetic nanoparticles.
authors.affiliation: Institute of Magnetism, National Academy of Science of Ukraine and Ministry for Education and Science of Ukraine, Vernadsky Blvd. 36-b, Kyiv, 03680, Ukraine. ksm@imag.kiev.ua.
authors.forename: S M
authors.initials: SM
authors.lastname: Konoplyuk
authors.affiliation: Institute of Magnetism, National Academy of Science of Ukraine and Ministry for Education and Science of Ukraine, Vernadsky Blvd. 36-b, Kyiv, 03680, Ukraine.
authors.forename: L E
authors.initials: LE
authors.lastname: Kozlova
authors.affiliation: Institute of Magnetism, National Academy of Science of Ukraine and Ministry for Education and Science of Ukraine, Vernadsky Blvd. 36-b, Kyiv, 03680, Ukraine.
authors.forename: V V
authors.initials: VV
authors.lastname: Kokorin
authors.affiliation: G.V. Kurdyumov Institute for Metal Physics, National Academy of Science of Ukraine, Vernadsky Blvd. 36, Kyiv, 03680, Ukraine.
authors.forename: A O
authors.initials: AO
authors.lastname: Perekos
authors.affiliation: Department of Physics, Lviv Polytechnic National University, S. Bandery Str. 12, Lviv, 79013, Ukraine.
authors.forename: O V
authors.initials: OV
authors.lastname: Kolomiets
keywords: Cu-Mn-Al; Granular system; Magnetoresistance; Superparamagnetism