Synthesis and characterization of Y Temperature ...
1
-10000 -5000 0 5000 10000 -0,020 -0,015 -0,010 -0,005 0,000 0,005 0,010 0,015 0,020 Y123 Moment (emu/g) Magnetic Field (Oe) 50 100 150 200 250 300 -0,00035 -0,00030 -0,00025 -0,00020 -0,00015 -0,00010 -0,00005 0,00000 0,00005 50 100 150 200 250 300 ZFC Moment (emu) x=0.5 FC Temperature (K) Synthesis and characterization of Y (1-x) Nd x Ba 2 Cu 3 O 7-δ High Temperature Superconductors by Acetate Method A. C. de Léo 1 , M. P. Nascimento 2 , U. D. Chacón 2 , E. M. B. Saitovitch 2 , M. Fontes 2 , M. A. Neves 3 , A. López 1 1 Universidade do Estado do Rio de Janeiro, Instituto de Física Armando Dias Tavares, RJ, Brazil. 2 Centro Brasileiro de Pesquisas Físicas, RJ, Brazil. 3 LMDS / Universidade Federal Rural do Rio de Janeiro, RJ, Brazil. e-mail: [email protected] Abstract: The REBCO (RE = Rare Earth) powder materials have a great application on industries, especially used as fault current limiters, current leads and levitators for electrical enhances and generators. In this work is presented an efficient process and results that may contribute to improve superconducting materials of optimum quality to Melt-Textured-Growth (MTG), which are suitable for many applications. Polycrystalline bulk samples of Y (1-x) Nd x Ba 2 Cu 3 O 7-δ were obtained by a wet-chemical acetate method with x = 0, 0,1, 0,2, 0,5 and 1,0 as well as change the Yttrrium for the rare earth Neodymium until full replacements i.e., from YBCO to NdBCO. The acetate route consists of a wet chemical procedure reaction with the powder Y 2 O 3 , Nd 2 O 3 , BaCO 3 and CuO (99,9% purity) into a solution of 50% glacial acetic acid. This method improves the grain growth, is shorter than conventional solid state method without any degradation in sample parameters. The samples were submitted to X-ray powder diffraction (XRD) and the spectra obtained were fitted using Rietveld method, orthorhombic space group Pmmm was assumed, the result showed that the unitary cell average volume increases with the Neodymium doping quantity. The porosity of the samples was calculated with densities from the sample and XRD data, and the values are from 11% up to 23%, resulting into a high degree of granularity in those samples. Those result shows that are fewer necks on the samples than expected by conventional method synthesis, confirmed by SEM images of cross section and superficial surfaces. It also provides information of the grains size and homogeneity. AC electrical resistance as a function of temperature measurements and DC magnetization measurements showed that all sampleshad superconducting transition with T C >77 K, and in absence of Neodymium, the critical temperature reaches 91K. From the analysis of the results we conclude that this method is promising for obtaining optimal high temperature superconducting cuprates in order to be used for MTG. The X-ray diffractogram (after a Rietveld refinement) for samples of YBa 2 Cu 3 O 7-δ and NdBa 2 Cu 3 O 7-δ , showed orthorhombic crystal system and space group P m m m. Fig. 4 – Amplification of 2500x the straight section of the samples Y (1-x) Nd x Ba 2 Cu 3 O 7-δ : a) x=0; b) x=0.1; c) x=0.5 and d)x=1. Fig.2 – Resistivity versus temperature of the samples Y (1-x) Nd x Ba 2 Cu 3 O 7-δ : a) x=0; b) x=0.1; c) x=0.2 d) x=0.5 and e) x=1 Fig.1 – X-ray diffratogram after adjustment by Rietveld refinement of the samples. CBPF’s X-ray Laboratory, resistivity and magnetic measurements, LMDS’s Laboratory for SEM characterization. PeD ANEEL, CEMIG D, CEMIG GT, CTEEP, TAESA and TBE (D712:SUPERCABO Project) and FAPERJ for financial support. The YBa 2 Cu 3 O 7-δ compound was synthesized in 1987, and was the first superconductor which showed a critical temperature above the boiling point temperature of nitrogen. In its composition, Yttrium (Y) can be replaced by various rare earth ions, which exhibit similar properties. Samples of YBa 2 Cu 3 O 7-δ (Y-123) and NdBa 2 Cu 3 O 7-δ (Nd-123) were obtained by a liquid route of acetic acid solution in distilled water. The magnetic moment analysis performed in two steps obtained irreversibility temperatures in ZFC and FC curves for the samples. These measurements confirmed the diamagnetic property of all compounds obtained over the temperature range. Fig.3 – a) Hysteresis Loop of Y123 (absence of Nd); b) Magnetization measurements versus temperature of the samples Y 0.5 Nd 0.5 Ba 2 Cu 3 O 7-δ . The results allow one to conclude that the method of wet synthesis of acetate proposed is promising for obtaining high quality powders of superconducting RE123 system, usable as starting materials to obtain sputtering targets to thin or thick superconducting films as well for the production of bulk pieces for use as levitators or current leads. b) c) d) The resistivity versus temperature curves of AC for the samples Y-123 (a) and Nd-123 (b) are shown in Figure 2. a) b) x a (Å) b (Å) c (Å) V (Å 3 ) 0 3.858435 3.877067 11.679653 174.721 0.1 3.852419 3.879487 11.687979 174.682 0.2 3.872143 3.879525 11.705256 175.830 0.5 3.880576 3.891899 11.705530 176.786 1 3.901839 3.914003 11.725516 179.070 20 30 40 50 60 70 80 (a) 2 (degrees) (b) Intensity (a.u) (c) (d) (e) a) Table 1 – Lattice parameters and unitary cell volume of the samples. 0,000 0,005 0,010 0,015 0,020 0,025 0,000 0,005 0,010 0,015 0,020 0,025 0,030 0,00 0,01 0,02 0,03 0,04 0,05 0,00 0,01 0,02 0,03 0,04 0,05 0,06 0,07 0 25 50 75 100 125 150 175 200 225 250 275 300 0,0 0,1 0,2 0,3 0,4 0,5 x=0 T x=1 x=0.2 x=0.5 x=1 Resistivity (mm. Temperature (K) a) b) c) d) e) H c1 = 288.92 Oe
Transcript of Synthesis and characterization of Y Temperature ...
-10000 -5000 0 5000 10000
-0,020
-0,015
-0,010
-0,005
0,000
0,005
0,010
0,015
0,020
Y123
Mo
me
nt (e
mu
/g)
Magnetic Field (Oe)
50 100 150 200 250 300
-0,00035
-0,00030
-0,00025
-0,00020
-0,00015
-0,00010
-0,00005
0,00000
0,00005
50 100 150 200 250 300
ZFC
Mo
me
nt (e
mu
)
x=0.5
FC
Temperature (K)
Synthesis and characterization of Y(1-x)NdxBa2Cu3O7-δ High
Temperature Superconductors by Acetate Method A. C. de Léo1, M. P. Nascimento2, U. D. Chacón2, E. M. B. Saitovitch2, M. Fontes2, M. A. Neves3, A. López1
1Universidade do Estado do Rio de Janeiro, Instituto de Física Armando Dias Tavares, RJ, Brazil. 2Centro Brasileiro de Pesquisas Físicas, RJ, Brazil.
3LMDS / Universidade Federal Rural do Rio de Janeiro, RJ, Brazil.
e-mail: [email protected]
Abstract: The REBCO (RE = Rare Earth) powder materials have a great application on industries, especially used as fault current limiters, current leads and levitators for electrical enhances and generators. In this work is presented an efficient process and
results that may contribute to improve superconducting materials of optimum quality to Melt-Textured-Growth (MTG), which are suitable for many applications.
Polycrystalline bulk samples of Y(1-x)NdxBa2Cu3O7-δ were obtained by a wet-chemical acetate method with x = 0, 0,1, 0,2, 0,5 and 1,0 as well as change the Yttrrium for the rare earth Neodymium until full replacements i.e., from YBCO to NdBCO. The acetate
route consists of a wet chemical procedure reaction with the powder Y2O3, Nd2O3, BaCO3 and CuO (99,9% purity) into a solution of 50% glacial acetic acid. This method improves the grain growth, is shorter than conventional solid state method without any
degradation in sample parameters.
The samples were submitted to X-ray powder diffraction (XRD) and the spectra obtained were fitted using Rietveld method, orthorhombic space group Pmmm was assumed, the result showed that the unitary cell average volume increases with the
Neodymium doping quantity.
The porosity of the samples was calculated with densities from the sample and XRD data, and the values are from 11% up to 23%, resulting into a high degree of granularity in those samples. Those result shows that are fewer necks on the samples than
expected by conventional method synthesis, confirmed by SEM images of cross section and superficial surfaces. It also provides information of the grains size and homogeneity.
AC electrical resistance as a function of temperature measurements and DC magnetization measurements showed that all sampleshad superconducting transition with TC >77 K, and in absence of Neodymium, the critical temperature reaches 91K. From
the analysis of the results we conclude that this method is promising for obtaining optimal high temperature superconducting cuprates in order to be used for MTG.
The X-ray diffractogram (after a Rietveld
refinement) for samples of YBa2Cu3O7-δ
and NdBa2Cu3O7-δ, showed orthorhombic
crystal system and space group P m m m.
Fig. 4 – Amplification of 2500x the straight section of the samples Y(1-x)NdxBa2Cu3O7-δ : a) x=0;
b) x=0.1; c) x=0.5 and d)x=1.
Fig.2 – Resistivity versus temperature of the samples Y(1-x)NdxBa2Cu3O7-δ : a) x=0; b) x=0.1; c) x=0.2
d) x=0.5 and e) x=1
Fig.1 – X-ray diffratogram after
adjustment by Rietveld refinement of
the samples.
CBPF’s X-ray Laboratory, resistivity and magnetic measurements, LMDS’s Laboratory for SEM characterization. PeD ANEEL, CEMIG D,
CEMIG GT, CTEEP, TAESA and TBE (D712:SUPERCABO Project) and FAPERJ for financial support.
The YBa2Cu3O7-δ compound was synthesized in 1987, and was the first
superconductor which showed a critical temperature above the boiling point
temperature of nitrogen. In its composition, Yttrium (Y) can be replaced by
various rare earth ions, which exhibit similar properties. Samples of
YBa2Cu3O7-δ (Y-123) and NdBa2Cu3O7-δ (Nd-123) were obtained by a liquid
route of acetic acid solution in distilled water.
The magnetic moment analysis performed in two steps obtained
irreversibility temperatures in ZFC and FC curves for the samples. These
measurements confirmed the diamagnetic property of all compounds
obtained over the temperature range.
Fig.3 – a) Hysteresis Loop of Y123 (absence of Nd); b) Magnetization measurements versus
temperature of the samples Y0.5Nd0.5Ba2Cu3O7-δ.
The results allow one to conclude that the method of wet synthesis of
acetate proposed is promising for obtaining high quality powders of
superconducting RE123 system, usable as starting materials to obtain
sputtering targets to thin or thick superconducting films as well for the
production of bulk pieces for use as levitators or current leads.
b)
c) d)
The resistivity versus temperature curves of AC for the samples Y-123 (a)
and Nd-123 (b) are shown in Figure 2.
a) b)
x
a (Å) b (Å) c (Å) V (Å3)
0
3.858435
3.877067
11.679653
174.721
0.1
3.852419
3.879487
11.687979
174.682
0.2
3.872143
3.879525
11.705256
175.830
0.5
3.880576
3.891899
11.705530
176.786
1
3.901839
3.914003
11.725516
179.070
20 30 40 50 60 70 80
(a)
2 (degrees)
(b)
Inte
nsity (
a.u
)
(c)
(d)
(e)
a)
Table 1 – Lattice parameters and unitary cell volume of the samples.
0,0000,0050,0100,0150,0200,025
0,0000,0050,0100,0150,0200,0250,030
0,000,010,020,030,040,05
0,000,010,020,030,040,050,060,07
0 25 50 75 100 125 150 175 200 225 250 275 300
0,00,10,20,30,40,5
x=0
T
x=1
x=0.2
x=0.5
x=1
Re
sis
tivity (
mm
.
Temperature (K)
a)
b)
c)
d)
e)
Hc1= 288.92 Oe
