Browsing Τμήμα Μηχανικών Μηχανολογίας και Κατασκευαστικής / Department of Mechanical and Manufacturing Engineering by Author "Androulakis, J."
Now showing items 1-20 of 27
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Coexistence of ferromagnetic and glassy behavior in semiconducting LaNi 0.2Co 0.8O 3
Androulakis, J.; Katsarakis, N.; Giapintzakis, John (2002)Systematic dc and ac magnetic susceptibility studies have been performed on single-phase LaNi 0.2Co 0.8O 3 powder samples. Evidence of hysteresis loops supports the existence of ferromagnetic correlations that lead to a ...
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Comparative study of the magnetic and magnetotransport properties of a metallic and a semiconducting member of the solid solution LaNixCo1-xO3
Androulakis, J.; Katsarakis, N.; Viskadourakis, Z.; Giapintzakis, John (2003)A metallic and a semiconducting member of the solid solution LaNixCo1-xO3 (x=0.2, 0.6) with their magnetic and magnetotransport properties was investigated. The members of the perovskite solid solution were found on opposite ...
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Ferromagnetic and antiferromagnetic interactions in lanthanum cobalt oxide at low temperatures
Androulakis, J.; Katsarakis, N.; Giapintzakis, John (2001)Systematic dc and ac magnetic susceptibility studies have been performed on single-phase (formula presented) powder samples. Evidence is presented in support of the existence of ferromagnetic (FM1, FM2) and antiferromagnetic ...
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Growth of polycrystalline LaNi 1-xCo xO 3 (x = 0.3, 0.5) thin films on Si(100) by pulsed laser deposition
Androulakis, J.; Klini, A.; Manousaki, A.; Violakis, G.; Giapintzakis, John (2004)Polycrystalline LaNi 1_xCo xO 3 (x = 0.5, 0.3) thin films have been deposited on polished Si(lOO) substrates by pulsed laser deposition. The films are grown at 650°C in ambient oxygen pressure of 0.4 mbar with an incident ...
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Hall effect study of magnetoresistive perovskite LaNi0.5Co 0.5O3 thin films
Androulakis, J.; Giapintzakis, John (2004)We report on the Hall effect of LaNi0.5Co0.5O 3 magnetoresistive thin films grown on Si(100) substrates by pulsed laser deposition. The Hall resistivity exhibits sign reversals both in varying magnetic field and temperature, ...
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High thermoelectric performance of Bi2-xSbxTe3 bulk alloys prepared from non-nanostructured starting powders
Symeou, E.; Nicolaou, Ch.; Delimitis, A.; Androulakis, J.; Kyratsi, Theodora; Giapintzakis, John (2019)In this work, hot press and hot deformation were applied to p-type Bi2-xSbxTe3 (x = 1.5-1.8) starting powders that have not undergone nanostructuring processing. The effects of hot pressing and hot deformation, as well ...
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Indium oxide as a possible tunnel barrier in spintronic devices
Androulakis, J.; Gardelis, S.; Giapintzakis, John; Gagaoudakis, E.; Kiriakidis, G. (2005)We report the growth of ultra-thin indium oxide layers using the dc-magnetron sputtering method. We demonstrate that good quality tunnel barriers made of indium oxide can be routinely fabricated and employed in spintronic-related ...
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Influence of the nonmagnetic impurities on the spin-1 Heisenberg chain SrNi2V2O8 system
Giapintzakis, John; Androulakis, J.; Syskakis, E.; Papageorgiou, Th P.; Apostolopoulos, G.; Thanos, S.; Papastaikoudis, C. (2006)De-magnetization and heat capacity measurements on polycrystalline samples of SrNi2-xMgxV2O8 (x = 0 and 0.05) are reported. The magnetization data suggest that both compounds are S= 1 quasi one-dimensional Heisenberg ...
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Large positive magnetoresistance in nonstoichiometric NiMnSb thin films on silicon
Branford, W. R.; Clowes, S. K.; Syed, M. H.; Bugoslavsky, Y. V.; Gardelis, S.; Androulakis, J.; Giapintzakis, John; Grigorescu, C. E. A.; Berenov, A. V.; Roy, S. B.; Cohen, L. F. (2004)The transport properties of pulsed-laser-deposited NiMnSb films on silicon as a function of film thickness were discussed. It was found that a low-temperature upturn was observed in the resistivity for film thicknesses of ...
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LaSrMnCoO6: A new cubic double perovskite oxide
Androulakis, J.; Katsarakis, N.; Giapintzakis, John; Vouroutzis, N.; Pavlidou, E.; Chrissafis, K.; Polychroniadis, E. K.; Perdikatsis, V. (2003)Single-phase polycrystalline powder samples of the double perovskite oxide LaSrMnCoO6 were synthesized by the Pechini (citrate-gel) technique. The structural, magnetic and electrical properties of the obtained powders were ...
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Low-temperature growth of NiMnSb thin films by pulsed-laser deposition
Giapintzakis, John; Grigorescu, C.; Klini, A.; Manousaki, A.; Zorba, V.; Androulakis, J.; Viskadourakis, Z.; Fotakis, C. (2002)We report the growth of thin films of the ferromagnetic half-Heusler alloy NiMnSb by pulsed-laser deposition on Si (111) and polycrystalline InAs substrates. Highly crystalline films are grown using low substrate temperatures ...
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Magnetic properties of the half-metallic ferromagnet NiMnSb grown on InSb by pulsed laser deposition
Androulakis, J.; Gardelis, S.; Giapintzakis, John; Buckle, P. D. (2004)We have grown films of the half-metallic ferromagnet NiMnSb on single crystals of the narrow gap semiconductor InSb by pulsed laser deposition. NiMnSb is a possible candidate for spin injection applications. The film ...
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Magneto-transport properties of NiMnSb thin films on InSb single crystals: Negative giant magnetoresistance
Gardelis, S.; Androulakis, J.; Viskadourakis, Z.; Papadopoulou, E. L.; Giapintzakis, John; Rai, S.; Lodha, G. S.; Roy, S. B. (2007)In this study we investigated the magneto-transport properties of the ohmic contact between polycrystal-line NiMnSb thin films grown by pulsed laser deposition and n-type degenerate InSb (100) substrates. An unusual negative ...
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Magnetoresistance in LaNi1-xCoxO3 (0.3≤x≤0.6)
Androulakis, J.; Giapintzakis, John (2010)We report on a detailed study of the electrical resistivity and the magnetoresistance of the metallic members of the LaNi1-xCoxO3 series with 0.3≤x≤0.6. The low-temperature resistivity of the compounds with 0.3≤x≤0.5 ...
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Negative giant longitudinal magnetoresistance in NiMnSb InSb: Interface effect
Gardelis, S.; Androulakis, J.; Viskadourakis, Z.; Papadopoulou, E. L.; Giapintzakis, John; Rai, S.; Lodha, G. S.; Roy, S. B. (2006)We report on the electrical and magnetotransport properties of the contact formed between n -type degenerate InSb (100) substrates and polycrystalline NiMnSb thin films grown using pulsed laser deposition. Negative giant ...
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Possible use of the half-Hausler alloy NiMnSb in spintronics: Synthesis and physical properties of arc melted NiMnSb and of NiMnSb thin films grown on InSb by pulsed laser deposition
Gardelis, S.; Androulakis, J.; Monnereau, O.; Buckle, P. D.; Giapintzakis, John (2005)We report the growth of single-phase, stoichiometric polycrystalline thin films of the half-Heusler ferromagnet NiMnSb, predicted to be half-metallic, on single crystal (100) InSb substrates heated at 200 °C by pulsed laser ...
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Article
Pulsed laser deposition and thermal characterization of Ni-doped La5Ca9Cu24O41 thin films
Athanasopoulos, G. I.; Pervolaraki, M.; Svoukis, E.; Androulakis, J.; Saint-Martin, R.; Revcolevschi, A.; Giapintzakis, John (2011)Highly b-axis oriented polycrystalline Ni-doped La5Ca 9Cu24O41 thin films have been grown on (0 0 1) SrTiO3 substrates using the pulsed laser deposition technique. EDX measurements have revealed nearly stoichiometric ...
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Pulsed-laser deposition of NiMnSb thin films at moderate temperatures
Giapintzakis, John; Grigorescu, C.; Klini, A.; Manousaki, A.; Zorba, V.; Androulakis, J.; Viskadourakis, Z.; Fotakis, C. (2002)Thin films of the half-Heusler alloy NiMnSb, which is predicted by band-structure calculations to be a half-metallic ferromagnet, were grown on various substrates (Si and InAs) using pulsed-laser deposition. The growth ...
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Realization of La2MnVO6: Search for half-metallic antiferromagnetism?
Androulakis, J.; Katsarakis, N.; Giapintzakis, John (2002)Single-phase polycrystalline La2MnVO6 samples were synthesized by arc-melting and characterized by X-ray diffraction, magnetization and resistivity measurements. We find that the compound has cubic (space group Fm3̄m), ...
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Recent advances in spintronics. Half-metal ferromagnets: Their role in spintronics
Gardelis, S.; Androulakis, J.; Migiakis, P.; Giapintzakis, John (2004)A review of recent advances in spintronics is presented. We report the structural, magnetic, electrical and thermal properties of the ferromagnetic half-Heusler alloy NiMnSb grown by arcmelting. The bulk material is used ...