The Effect of Ar Ambient Pressure and Annealing Duration on the Microstructure, Superconducting Properties and Activation Energies of MgB2 Superconductors

ÖZTÜRK, Özgür; AŞIKUZUN TOKEŞER, Elif; KAYA, Şeydanur; Koc, N. S.; Erdem, M.

doi:10.1007/s10948-016-3877-4

The Effect of Ar Ambient Pressure and Annealing Duration on the Microstructure, Superconducting Properties and Activation Energies of MgB2 Superconductors

Yazarlar (5)

Prof. Dr. Özgür ÖZTÜRK Kastamonu Üniversitesi, Türkiye

Doç. Dr. Elif AŞIKUZUN TOKEŞER Kastamonu Üniversitesi, Türkiye

Öğr. Gör. Dr. Şeydanur KAYA Kastamonu Üniversitesi, Türkiye

N. S. Koc
Bolu Abant İzzet Baysal Üniversitesi, Türkiye

M. Erdem
Bolu Abant İzzet Baysal Üniversitesi, Türkiye

Makale Türü	Özgün Makale (SSCI, AHCI, SCI, SCI-Exp dergilerinde yayınlanan tam makale)
Dergi Adı	Journal of Superconductivity and Novel Magnetism (Q3)
Dergi ISSN	1557-1939 Dergi Bilgileri (2017)
Dergi Tarandığı Indeksler	SCI-Expanded
Makale Dili	İngilizce	Basım Tarihi	05-2017
Kabul Tarihi	–	Yayınlanma Tarihi	19-12-2016
Cilt / Sayı / Sayfa	30 / 5 / 1161–1169	DOI	10.1007/s10948-016-3877-4
Makale Linki	http://link.springer.com/10.1007/s10948-016-3877-4
UAK Araştırma Alanları	Yarı İletkenler

Özet

MgB2 samples are produced by ex situ reaction method under vacuum, and various (0, 10, 20 Bar) Ar pressure for 0.5 and 1 h. The effect of ambient pressure and annealing duration on the microstructure and electrical properties of bulk samples are investigated. XRD, SEM, and magnetoresistance measurements are made. The a and c lattice parameters and the grain size values are the highest for the samples produced under vacuum and their values decrease with increasing Ar pressure. Moreover, these values increase when the annealing duration increases from 0.5 to 1 h. The increasing pressure reduces the bond lengths between the atoms thus the grain sizes decrease. Smaller grain size promotes the connection between grains which results in an increase of the critical current density (Jc). SEM micrographs reveal that the produced samples have granular structure which is a characteristic feature of MgB2. The decrease of grain sizes and thus enhancement in grain connectivity with increasing pressure is also confirmed by SEM images. Magneto resistivity measurements show that Tc values of the samples produced under vacuum are the highest. Tc values decrease with increasing ambient pressure and applied magnetic field. The activation energies (U0) of the samples are calculated using Arrhenius plots due to thermally activated flux flow theory. Existence and increase of Ar pressure causes increase of activation energies. The samples produced with 0.5-h annealing have higher activation energies than the ones produced with 1-h annealing.

Anahtar Kelimeler

Activation energy | Magnetoresistivity | MgB2 | Superconductivity

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BM Sürdürülebilir Kalkınma Amaçları

Atıf Sayıları
Scopus	5

The Effect of Ar Ambient Pressure and Annealing Duration on the Microstructure, Superconducting Properties and Activation Energies of MgB2 Superconductors

Dergi Adı	Journal of Superconductivity and Novel Magnetism
Kısa Adı	J SUPERCOND NOV MAGN
Yayıncı	SPRINGER
Açık Erişim	Hayır
ISSN	1557-1939
E-ISSN	1557-1947
Wos Quartile	Q3
Scopus Quartile	Q3
Tarandığı Indeksler	SCIE , Scopus
WoS Kategoriler	PHYSICS, APPLIED \| PHYSICS, CONDENSED MATTER
Scopus Kategoriler	CONDENSED MATTER PHYSICS \| ELECTRONIC, OPTICAL AND MAGNETIC MATERIALS

The Effect of Ar Ambient Pressure and Annealing Duration on the Microstructure, Superconducting Properties and Activation Energies of MgB2 Superconductors

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