Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase
Ferromagnetic nickel (Ni) nanoparticles were added in (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ (CuTl-1223) superconducting matrix to get Nix/CuTl-1223; x = 0–1.00 wt% nanoparticles-superconductor composites. Temperature- and frequency-dependent dielectric properties of CuTl-1223 superconducting phase with differe...
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Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2018
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irk-123456789-1762162021-02-05T01:30:22Z Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase Mumtaz, M. Asghar, M.A. Свеpхпpоводимость, в том числе высокотемпеpатуpная Ferromagnetic nickel (Ni) nanoparticles were added in (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ (CuTl-1223) superconducting matrix to get Nix/CuTl-1223; x = 0–1.00 wt% nanoparticles-superconductor composites. Temperature- and frequency-dependent dielectric properties of CuTl-1223 superconducting phase with different contents of Ni nanoparticles were studied. Different dielectric parameters such as dielectric constant (ε′r,ε′′r), dielectric tangent loss (tan δ) and ac conductivity (σac) were determined from experimentally measured capacitance and conductance at different frequencies from 10 kHz to 10 MHz and at different operating temperatures from 78 to 290 K. The values of ε′r and ε′′r were found maximal at smaller frequencies and started to decrease at higher frequencies. The value of σac is high at high frequency unlike to ε′r and ε′′r, which is due to release of space charges at high frequencies. Peaks in tan δ graphs represent the resonance phenomenon at certain frequencies in these samples. Non-monotonic behavior in variation of dielectric parameters with temperature of Nix/CuTl-1223 samples was observed particularly at high temperatures which was due to thermal instability of the system at high temperatures. Для отримання композитів наночастинка– надпровідник Nix /CuTl-1223 (x = 0–1,00 мас.%) в надпровідну матрицю (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ (CuTl-1223) було додано феромагнітні наночастинки Ni. Вивчено температурно- та частотно-залежні діелектричні властивості надпровідної фази CuTl1223 з різним вмістом наночастинок Ni. Різні діелектричні параметри, такі як діелектрична стала ( r ε′ , r ε′′ ), діелектричні тангенціальні втрати (tg δ) та провідність змінного струму (σac), визначалися по експериментально виміряних ємності та провідності на різних частотах від 10 кГц до 10 МГц при різних робочих температурах від 78 до 290 К. Значення r ε′ та r ε′′ були максимальні при менших частотах та зменшувалися при більш високих частотах. Значення σac, на відміну від r ε′ та r ε′′ , було високе на високій частоті, що пов’язано з виходом об’ємних зарядів на високих частотах. Піки на tg δ графіках представляють собою резонанс на деяких частотах в цих зразках. Немонотонна поведінка температурних залежностей діелектричних параметрів зразків Nix/CuTl-1223 спостерігалася, зокрема, при високих температурах, що викликано тепловою нестійкістю системи. 2018 Article Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase / M. Mumtaz, M.A. Asghar // Физика низких температур. — 2018. — Т. 44, № 8. — С. 970-977. — Бібліогр.: 20 назв. — англ. 0132-6414 PACS: 74.25.–q, 74.25. F–, 74.72.–h, 74.81.Bd http://dspace.nbuv.gov.ua/handle/123456789/176216 en Физика низких температур Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
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Свеpхпpоводимость, в том числе высокотемпеpатуpная Свеpхпpоводимость, в том числе высокотемпеpатуpная |
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Свеpхпpоводимость, в том числе высокотемпеpатуpная Свеpхпpоводимость, в том числе высокотемпеpатуpная Mumtaz, M. Asghar, M.A. Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase Физика низких температур |
| description |
Ferromagnetic nickel (Ni) nanoparticles were added in (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ (CuTl-1223) superconducting matrix to get Nix/CuTl-1223; x = 0–1.00 wt% nanoparticles-superconductor composites. Temperature- and frequency-dependent dielectric properties of CuTl-1223 superconducting phase with different contents of Ni nanoparticles were studied. Different dielectric parameters such as dielectric constant (ε′r,ε′′r), dielectric tangent loss (tan δ) and ac conductivity (σac) were determined from experimentally measured capacitance and conductance at different frequencies from 10 kHz to 10 MHz and at different operating temperatures from 78 to 290 K. The values of ε′r and ε′′r were found maximal at smaller frequencies and started to decrease at higher frequencies. The value of σac is high at high frequency unlike to ε′r and ε′′r, which is due to release of space charges at high frequencies. Peaks in tan δ graphs represent the resonance phenomenon at certain frequencies in these samples. Non-monotonic behavior in variation of dielectric parameters with temperature of Nix/CuTl-1223 samples was observed particularly at high temperatures which was due to thermal instability of the system at high temperatures. |
| format |
Article |
| author |
Mumtaz, M. Asghar, M.A. |
| author_facet |
Mumtaz, M. Asghar, M.A. |
| author_sort |
Mumtaz, M. |
| title |
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase |
| title_short |
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase |
| title_full |
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase |
| title_fullStr |
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase |
| title_full_unstemmed |
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase |
| title_sort |
dielectric properties of ferromagnetic ni nanoparticles added (cu₀.₅tl₀.₅)ba₂ca₂cu₃o₁₀₋δ superconducting phase |
| publisher |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України |
| publishDate |
2018 |
| topic_facet |
Свеpхпpоводимость, в том числе высокотемпеpатуpная |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/176216 |
| citation_txt |
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu₀.₅Tl₀.₅)Ba₂Ca₂Cu₃O₁₀₋δ superconducting phase / M. Mumtaz, M.A. Asghar // Физика низких температур. — 2018. — Т. 44, № 8. — С. 970-977. — Бібліогр.: 20 назв. — англ. |
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Физика низких температур |
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AT mumtazm dielectricpropertiesofferromagneticninanoparticlesaddedcu05tl05ba2ca2cu3o10dsuperconductingphase AT asgharma dielectricpropertiesofferromagneticninanoparticlesaddedcu05tl05ba2ca2cu3o10dsuperconductingphase |
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2025-07-15T13:53:58Z |
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2025-07-15T13:53:58Z |
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1837721336294670336 |
| fulltext |
Low Temperature Physics/Fizika Nizkikh Temperatur, 2018, v. 44, No. 8, pp. 970–976
Dielectric properties of ferromagnetic Ni nanoparticles
added (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ superconducting phase
M. Mumtaz and Mian A. Asghar
Materials Research Laboratory, Department of Physics, Faculty of Basic and Applied Sciences (FBAS)
International Islamic University (IIU), Islamabad 44000, Pakistan
E-mail: mmumtaz75@yahoo.com
Received November 30, 2017, revised February 15, 2018, published online June 27, 2018
Ferromagnetic nickel (Ni) nanoparticles were added in (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ (CuTl-1223) supercon-
ducting matrix to get Nix/CuTl-1223; x = 0–1.00 wt% nanoparticles-superconductor composites. Temperature-
and frequency-dependent dielectric properties of CuTl-1223 superconducting phase with different contents of Ni
nanoparticles were studied. Different dielectric parameters such as dielectric constant ( r′ε , r′′ε ), dielectric tangent
loss (tan δ) and ac conductivity (σac) were determined from experimentally measured capacitance and conduct-
ance at different frequencies from 10 kHz to 10 MHz and at different operating temperatures from 78 to 290 K.
The values of r′ε and r′′ε were found maximal at smaller frequencies and started to decrease at higher fre-
quencies. The value of σac is high at high frequency unlike to r′ε and r′′ε , which is due to release of space
charges at high frequencies. Peaks in tan δ graphs represent the resonance phenomenon at certain frequen-
cies in these samples. Non-monotonic behavior in variation of dielectric parameters with temperature of
Nix/CuTl-1223 samples was observed particularly at high temperatures which was due to thermal instability of
the system at high temperatures.
PACS: 74.25.–q Properties of superconductors;
74.25. F– Transport properties;
74.72.–h Cuprate superconductors;
74.81.Bd Granular, melt-textured, amorphous, and composite superconductors.
Keywords: Nix/(CuTl-1223) composites, Ni nanoparticles, CuTl-1223 superconductor, dielectric properties.
1. Introduction
The dielectric properties of superconducting materials can
play a vital role in growth of microelectronics to produce
various robust devices such as memory devices and capaci-
tor [1]. High values of dielectric constant of various high-
temperature superconductors (HTSCs) made them highly
suitable for practical applications in the field of electronics
[2–5]. Different phases of Cu0.5Tl0.5Ba2Can–1CunO2n+4–δ
HTSCs family can be synthesized at high pressure (~5 GPa)
as well as at ambient pressure. The values of supercon-
ducting parameters of the materials synthesized at high-
pressure are normally higher than those synthesized at am-
bient pressure [6]. The high pressure synthesis can play an
important role for carriers’ optimization and to enhance
superconductivity [7,8]. The easy ambient pressure synthe-
sis was the main motivation to select CuTl-1223 phase of
CuTl-12(n–1)n HTSCs family for the study of dielectric
properties of this phase [9,10]. In various electronic devic-
es the conduction mechanisms strongly depends upon the
frequency, temperature, surface charges, fabrication condi-
tions, impurities and doping concentration. Therefore, it
has become mandatory to study the dielectric properties of
HTSCs over an extensive frequency and temperature rang-
es, which can yield useful information about their polariza-
tion and conduction mechanism. There are four primary
mechanisms of polarizations: (i) electronic polarization
(αe), (ii) atomic and ionic polarization (αa), (iii) dipolar
and oriental polarization (αo) and (iv) interfacial polariza-
tion (αi) [11,12]. A short-range motion of charges in each
mechanism of polarization leads to the total polarization.
Interfacial polarization and oriental or dipolar polarization
is generally active in HTSCs because at high frequency the
dielectric constant becomes saturated for a temperature
range from superconducting state to room temperature.
There are various techniques reported in literature to
tune the dielectric properties of HTSCs but one of the easi-
est and very effective methods is the insertion of different
© M. Mumtaz and Mian A. Asghar, 2018
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ superconducting phase
nanostructures in appropriate amount at the grain bounda-
ries of HTSCs matrices. Carrier density can be controlled
in the material by varying the content of nanostructures at
inter-granular sites. The nature of grain boundaries, oxygen
contents, grains size and inter-grains connectivity of bulk
HTSCs can also be influenced by the inclusion of
nanostructures [13,14].
In present article, the effects of ferromagnetic Ni nano-
particles on the dielectric properties of CuTl-1223 super-
conducting phase have been explored at different tempera-
tures from 78 to 290 K and different frequencies from
10 kHz to 10 MHz. These nanoparticles can modify the
nature of grain boundaries, grain size, inter-grain weak-
links and oxygen contents, which can affect the supercon-
ducting and dielectric parameters of CuTl-1223 phase.We
tried to tune the dielectric properties of CuTl-1223 phase
by varying the content of ferromagnetic Ni nanoparticles,
temperature and frequency.
2. Samples synthesis and experimental details
Cu0.5Tl0.5Ba2Ca2Cu3O10–δ (CuTl-1223) superconduct-
ing phase was synthesized by solid-state reaction and
nickel nanoparticles were prepared by sol-gel methods.
These ferromagnetic Ni nanoparticles were added in CuTl-
1223 matrix to get Nix/CuTl-1223; x = 0, 0.25, 0.5, 0.75
and 1.00 wt% superconductor-nanoparticles composites.
These samples were characterized by using different exper-
imental techniques such as x-rays diffraction (XRD), resis-
tivity vs temperature measurements, scanning electron mi-
croscopy (SEM) and energy dispersive x-ray spectroscopy
(EDX) [15].
The instrument used to measure the inductance (L), ca-
pacitance (C) and resistance (R) is commonly written as
LCR meter. The frequency dependent dielectric measure-
ments were carried out by LCR meter (Hewlett-Packard
4294A) in frequency range from 10 kHz to 10 MHz at dif-
ferent operating temperatures from 78 to 290 K. A conven-
tional two-probe technique was used for these dielectric
measurements. Silver paint was applied on both surfaces of
rectangular bar-shaped sample and copper leads contacts
were made by silver paint on two silver electrode surfaces
of the sample.
3. Results and discussions
Structural, compositional, morphological and supercon-
ducting transport properties of Nix/CuTl-1223 composites
samples were carried out by XRD, EDX, SEM and four-
point probe resistivity vs temperature measurements and
reported in our previously published manuscript [15].
In this articles, we are reporting only the frequency-
and temperature-dependent dielectric properties of
Nix/CuTl-1223; x = 0, 0.25, 0.5, 0.75 and 1.00 wt% super-
conductor-nanoparticles composites in frequency range
from 10 kHz to 10 MHz at different operating tempera-
tures from 78 to 290 K. The change in the values of r′ε and
r′′ε , tan δ and σac by varying the contents of Ni nanoparti-
cles from x = 0 to 1.00 wt%, were determined, compared
and explained. The energy stored in the sample when ex-
posed to external applied ac field is represented by real
part of the dielectric constant (i.e., r′ε = Cd/A 0ε ). Where C
is capacitance (F), d is the thickness of the dielec-
tric/separation between the plates of the capacitor (m), 0ε
is the permittivity of free space ( 0ε = 8.85⋅10–12 F/m) and
A is the area of the electrode (m2). Variation in r′ε of
Nix/CuTl-1223 composites with different test frequencies
and operating temperatures is shown in Figs. 1(a)–(e). The
value of r′ε is higher at lower frequencies demonstrating
the gradual decrease with the increase in frequency and
becomes almost zero at higher frequency indicating that
the time period of applied ac signal becomes smaller than
the time required for polarization. Active grain boundaries
are responsible for high values of real part of dielectric
constant at lower frequencies [16–18]. As space charge
carriers need finite time for alignment in the direction of
applied ac electric field, so r′ε showed decreasing trend
with increasing frequency of external applied ac field.
Maximum values of r′ε at lower frequency of 10 kHz var-
ied from 3.4⋅105 to 3.6⋅103, 1.07⋅104 to 2.28⋅103, 2.5⋅105 to
4.25⋅104, 7.76⋅104 to 1.3⋅104 and 6.3⋅105 to 1.8⋅104 at various
operating temperature from 78 to 290 K for Nix/CuTl-1223
composites with x = 0, 0.25, 0.50, 0.75 and 1.00 wt%,
respectively. Overall decreasing trend in r′ε with addi-
tion of Ni nanoparticles was observed with some non-
monotonic behavior at different operating temperatures.
Particularly, at higher temperatures the system was be-
come thermally unstable due to which a slight anoma-
lous behavior in variation of r′ε with T was observed.
Comparison of variation in maximum values of r′ε with
different contents of Ni nanoparticles at different ope-
rating temperature is shown in Fig. 1(f). The suppression
in the values of r′ε was observed up to x = 0.75 wt% and
an increase was observed in the sample with maximum Ni
nanoparticles, i.e., x = 1.00 wt%. The high values of r′ε for
the sample with x = 1.0 wt% of Ni nanoparticles can be
caused by maximum trapping of mobile charge carriers at
grain boundaries due to magnetic interaction with these
magnetic Ni nanoparticles present there.
The loss or attenuation of energy across the interfac-
es of the samples in an external applied electric ac field
can be estimated by the imaginary part of the dielectric
constant ( r′′ε = Gd/(ωA 0ε )). Where G is conductance and
ω (= 2πf) is the angular frequency. Conductance is an
expression of the ease with which electric current flows
through any material and is the reciprocal of resistance
R. The standard unit of conductance is Siemens (S). The
variation of r′′ε with test frequency from 10 kHz to
10 MHz at different operating temperatures from 78 to
290 K of Nix/CuTl-1223 composites samples are shown
in Fig. 2(a)–(e). A decreasing trend in r′′ε has been ob-
Low Temperature Physics/Fizika Nizkikh Temperatur, 2018, v. 44, No. 8 971
https://en.wikipedia.org/wiki/Antiferromagnetic
https://en.wikipedia.org/wiki/Inductance
https://en.wikipedia.org/wiki/Capacitance
https://en.wikipedia.org/wiki/Capacitance
https://en.wikipedia.org/wiki/Electrical_resistance
M. Mumtaz and Mian A. Asghar
served with increasing frequency, which is in accordance
with Wagner and Koop’s theory [19,20]. According to
these models, dielectric medium is a combination of well
conducting grains and poorly conducting grain boundaries.
The grain boundaries are responsible for high value of r′′ε
at lower frequencies. The maximum value of r′′ε at lower
frequency of 10 kHz varied from 4.79⋅106 to 1.1⋅106,
9.9⋅105 to 6.3⋅105, 5.6⋅106 to 4.99⋅105, 5.78⋅106 to 2.9⋅106
and 1.05⋅107 to 5.5⋅106 at different operating temperatures
from 78 to 290 K for Nix/CuTl-1223 composites with
x = 0, 0.25, 0.50, 0.75 and 1.00 wt%, respectively. At low-
er frequencies, the value of r′′ε was found to be highest,
which was gradually decreased with the increase of fre-
quency and became linear with very lower values at higher
frequencies. This was because at lower frequency the carri-
ers can follow the frequency of external applied ac field
and at high frequency the time period become very short
and most of the carriers can’t follow the external electric
frequency and the response of the material becomes very
small. Variation in maximum value of r′′ε at lower frequen-
cy of 10 kHz versus operating temperatures is shown in
Fig. 2(f). Maximum values of r′′ε initially decreases with
the addition of Ni nanoparticles at all operating tempera-
tures and then starts to increase with higher content of the-
se nanoparticles contents. Increase in maximum value of r′′ε
at x = 0.75 and 1.00 wt% showed enhanced energy loss due
to high potential barrier offered by ferromagnetic Ni nano-
particles present at grain boundaries. The mobile charge
carriers can be trapped across grain boundaries due mag-
netic interaction of Ni nanoparticles and large energy loss
can take place at higher contents of Ni nanoparticles in
CuTl-1223 matrix.
Fig. 1. Variation in r′ε as a function of frequency at different operating temperatures of Nix/CuTl-1223 composites with (a) x = 0;
(b) x = 0.25 wt%; (c) x = 0.50 wt%; (d) x = 0.75 wt%; (e) x = 1.00 wt% and (f) variation of maximum r′ε at 10 kHz with operating
temperature.
972 Low Temperature Physics/Fizika Nizkikh Temperatur, 2018, v. 44, No. 8
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ superconducting phase
Dielectric tangent loss ( )tan /r r′′ ′δ = ε ε is the ratio of
energy dissipated to energy stored in material when ex-
posed to ac field. Variation of tanδ with frequency from
10 kHz to 10 MHz at different operating temperatures from
78 to 290 K of Nix/CuTl-1223 composites is shown in
Figs. 3(a)–(e). Value of tanδ is very small and almost
constant at low frequency and a peak is observed for all
these samples in frequency range from 105 to 107 Hz,
which was due to resonance phenomenon resulting from
the superposition of hooping frequency of charge carriers
with frequency of external applied electric ac field. Varia-
tion in tanδ at 10 kHz with operating temperature of these
samples is shown in Fig. 3(f). Maximum values of tanδ
were observed at higher operating temperatures for all the-
se samples. Overall increase in tanδ showed the enhanced
potential barriers at grain boundaries with the addition of
ferromagnetic Ni nanoparticles in CuTl-1223 supercon-
ducting host matrix. At high temperature the system may
become unstable due to which a slight anomalous behavior
has been witnessed.
Variation in ac conductivity (σac) with frequency from
10 kHz to 10 MHz at different operating temperatures from
78 to 290 K of Nix/CuTl-1223 composites is shown in
Figs. 4(a)–(e). Prominent increase in σac was observed at
higher frequencies, which was attributed to strong conduc-
tion mechanism by hooping of charge carriers. Maximum
value of σac (s/m) varied from 4.75⋅10–3 to 6.17⋅10–7,
1.7⋅10–4 to 1.27⋅10–5, 2.08⋅10–3 to 4.2⋅10–6, 5.8⋅10–4 to
3.7⋅10–6 and 1.3⋅10–2 to 9.3⋅10–6 at maximum frequency of
10 MHz with different operating temperatures from 78 to
290 K for Nix/CuTl-1223 composites with x = 0, 0.25,
0.50, 0.75 and 1.00 wt%, respectively. Variation of maxi-
Fig. 2. Variation in r′′ε as a function of frequency at different operating temperatures of Nix/CuTl-1223 composites with (a) x = 0;
(b) x = 0.25 wt%; (c) x = 0.50 wt%; (d) x = 0.75 wt%; (e) x = 1.00 wt% and (f) variation of maximum r′′ε 10 kHz with operating
temperature.
Low Temperature Physics/Fizika Nizkikh Temperatur, 2018, v. 44, No. 8 973
M. Mumtaz and Mian A. Asghar
mum σac as a function of operating temperatures is shown
in Fig. 4(f). Increase in maximum value of σac was ob-
served at higher operating temperatures, which shows en-
hanced conduction mechanism due to thermal excitation.
Overall suppression in σac was observed at higher contents
of ferromagnetic Ni nanoparticles in CuTl-1223 supercon-
ducting matrix for all operating temperatures, which
showed the enhanced resistance in the transportation of car-
riers due to increased barriers across the grain boundaries
with these ferromagnetic Ni nanoparticles. Maximum value
σac has initially been increased for x = 0.25 and 0.75 wt%
and then started to decrease at higher contents due to en-
hanced trapping mechanism promoted by the strong inter-
action of magnetic Ni nanoparticles settled at grain bound-
aries of the host CuTl-1223 matrix. The slight anomalous
trend in variation of σac at higher temperature can be at-
tributed to thermal instability of the system.
4. Conclusion
Nix/CuTl-1223 nanoparticles-superconductor compo-
sites were synthesized and their dielectric properties were
explored at different operating temperatures and frequen-
cies. The values of r′ε and r′′ε were decreased with addi-
tion of Ni nanoparticles at low concentration and en-
hancement was observed at high concentrations. The
values of tanδ were increased with inclusion of Ni nano-
particles in CuTl-1223 superconductor. Occurring of reso-
nance phenomenon was evidenced from the peaks in tanδ
graphs at certain frequencies in all Nix/CuTl-1223 samples
resulting from the superposition of hooping frequency of
charge carriers with frequency of external applied electric
ac field. Higher content of Ni nanoparticles at grain
boundaries created higher barriers to the mobility of charge
carriers, which reduced the ac conduction and enhanced
Fig. 3. Variation in tanδ as a function of frequency at different operating temperatures of Nix/CuTl-1223 composites with (a) x = 0;
(b) x = 0.25 wt%; (c) x = 0.50 wt%; (d) x = 0.75 wt%; (e) x = 1.00 wt% and (f) variation of tanδ at 10 kHz with operating temperature.
974 Low Temperature Physics/Fizika Nizkikh Temperatur, 2018, v. 44, No. 8
Dielectric properties of ferromagnetic Ni nanoparticles added (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ superconducting phase
loss factors in the materials. The variation in dielectric
properties can be attributed to the enhanced accumula-
tion of charge carriers across the grain boundaries of
CuTl-1223 superconducting phase due to magnetic inter-
action of ferromagnetic Ni nanoparticles present there. The
most probable reason for suppression of σac at high content
of Ni nanoparticles is the reduction of optimum carriers’
density desired for high conductivity after addition of these
magnetic Ni nanoparticles settled at grain boundaries.
So, we can tune the dielectric properties of CuTl-1223
superconductor by homogeneous distribution of nano-
structures at grain bombardiers, varying test frequency
and operating temperature according to the requirement
of applications.
________
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___________________________
Вплив додання феромагнітних наночастинок Ni
на діелектричні властивості надпровідної фази
(Cu0,5Tl0,5)Ba2Ca2Cu3O10–δ
M. Mumtaz and Mian A. Asghar
Для отримання композитів наночастинка–
надпровідник Nix /CuTl-1223 (x = 0–1,00 мас.%) в
надпровідну матрицю (Cu0,5Tl0,5)Ba2Ca2Cu3O10–δ
(CuTl-1223) було додано феромагнітні наночастин-
ки Ni. Вивчено температурно- та частотно-залежні
діелектричні властивості надпровідної фази CuTl-
1223 з різним вмістом наночастинок Ni. Різні діеле-
ктричні параметри, такі як діелектрична стала ( r′ε ,
r′′ε ), діелектричні тангенціальні втрати (tg δ) та про-
відність змінного струму (σac), визначалися по екс-
периментально виміряних ємності та провідності на
різних частотах від 10 кГц до 10 МГц при різних
робочих температурах від 78 до 290 К. Значення r′ε
та r′′ε були максимальні при менших частотах та
зменшувалися при більш високих частотах. Значен-
ня σac, на відміну від r′ε та r′′ε , було високе на висо-
кій частоті, що пов’язано з виходом об’ємних заря-
дів на високих частотах. Піки на tg δ графіках
представляють собою резонанс на деяких частотах в
цих зразках. Немонотонна поведінка температурних
залежностей діелектричних параметрів зразків
Nix/CuTl-1223 спостерігалася, зокрема, при високих
температурах, що викликано тепловою нестійкістю
системи.
Ключові слова: Nix /(CuTl-1223), наночастинки Ni,
надпровідник CuTl-1223, діелектричні властивості.
976 Low Temperature Physics/Fizika Nizkikh Temperatur, 2018, v. 44, No. 8
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https://doi.org/10.1063/1.2967823
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https://doi.org/10.1103/PhysRevB.70.172102
https://doi.org/10.1063/1.2757098
https://doi.org/10.1002/andp.19133450502
https://doi.org/10.1103/PhysRev.83.121
1. Introduction
2. Samples synthesis and experimental details
3. Results and discussions
4. Conclusion
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