Sintesis, Struktur Kristal Dan Sifat Magnetik Superkonduktor REBa2Cu3O7-0 (RE = Nd, Eu, Gd)

Suharta, Wayan Gede (2013) Sintesis, Struktur Kristal Dan Sifat Magnetik Superkonduktor REBa2Cu3O7-0 (RE = Nd, Eu, Gd). Doctoral thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

NdBa2Cu3O7-δ (Nd-123), NdxY1-xBa2Cu3O7-δ (NdxY1-x-123) and REBa2Cu3O7-δ (RE-123) superconductors have been successfully synthesized by means of wet-mixing method and HNO3 as digest agent. Nd-123 samples were calcined at 600oC for 3 hours, cooled and re-grounded. Characterization results of X-ray diffraction (XRD) for Nd- 123 samples (600oC) show impurity phase of Ba(NO3)2, BaCO3, Nd2O3, CuO, Nd2CuO4, Nd2BaO4, (Nd0,925Ba0,075)2CuO4-x, and Nd1,5Ba1,5Cu3O7,03, while the Nd-123 phase itself has not been detected at all. The addition of re-calcination temperatures (650-970oC) was applied to eliminate impurities and to grow the Nd-123 phase, in order to obtain an increase in the weight fraction of Nd-123 (84.3 to 95.9 %) phase. Based on these results, NdxY1-x-123 and RE-123 samples were calcined at 600oC for 3 hours, cooled and re-grounded, then followed by re-calcination temperature at 970oC for ten hours. Weight fractions obtained in NdxY1-x-123 samples were 96.6 to 97.0 %, while they were approximately 96.9 to 98.8 % in the RE-123 samples. Characterization of high-resolution neutron powder diffraction (HRPD) and synchrotron-ray diffraction (SRD) were conducted for the Rietveld analysis with Rietica and FullProf programs. Rietveld analysis results for NdxY1-x-123 samples showed that the addition of Nd element (x = 0-1) resulting in increased values of lattice parameters, unit cell volume and orthorhombisity, with the order from the smallest to the largest, namely Y-123, Nd0,25Y0,75-123, Nd0,5Y0,5-123, Nd0,75Y0,25-123 and Nd-123. The addition of Nd element on NdxY1-x-123 superconductors also resulted in the migration of oxygen as shown by reduced oxygen occupancy factor at the position of O(4). Rietveld analysis results of REBa2Cu3O7-δ, showed that the combination of RE resulted in changing the values of the lattice parameters and the unit cell volume, with the order from the smallest to the largest, ie Gd-123, Eu0,5Gd0,5-123, Eu-123, Nd0,33Eu0,33Gd0,33Ba2Cu3O7-δ, Nd0,5Gd0,5-123, Nd0,5Eu0,5-123 and Nd-123. Characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the addition of re-calcination temperatures resulted in larger particle sizes . Characterization results from superconducting quantum interference device (SQUID) measurements showed that resistance of superconducting property in a magnetic field of Nd0,5Y0,5Ba2Cu3O7-δ samples is greater than that of Nd0,25Y0,75Ba2Cu3O7-δ samples. Characterization results from vibrating sample magnetometer (VSM) for REBa2Cu3O7-δ samples with particle sizes smaller than 50 nm exhibit ferromagnetic properties at room temperature, while the sample with particle sizes larger than 100 nm shows paramagnetic properties. The addition of Nd element vii from x = 0,25 to become x = 0,5 in NdxY1-x-123 samples has increased the critical temperature Tc (from 90,5 to 91,5 K) and the critical current density Jc (from 4 × 104 Acm-2 to 1 × 105 Acm-2). The critical temperature of REBa2Cu3O7-δ samples are in the range of 88,5 and 93,6 K.

Item Type: Thesis (Doctoral)
Additional Information: RDFi 537.623 Suh s 3100014053479
Uncontrolled Keywords: Superconductor, wet-mixing method, re-calcination, ferromagnetic, XRD, SRD, HRPD, SQUID, critical temperature, critical current densitySuperconductor, wet-mixing method, re-calcination, ferromagnetic, XRD, SRD, HRPD, SQUID, critical temperature, critical current density
Subjects: Q Science > QC Physics > QC611.97.C54 Superconductors
Divisions: Faculty of Industrial Technology > Physics Engineering > 30001-(S3) PhD Thesis
Depositing User: - Davi Wah
Date Deposited: 16 Jan 2020 08:30
Last Modified: 16 Jan 2020 08:40
URI: http://repository.its.ac.id/id/eprint/72701

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