sarin kumar - Academia.edu (original) (raw)

Papers by sarin kumar

Research paper thumbnail of Highly Sensitive Carbon Nanotubes Coated Etched Fiber Bragg Grating Sensor for Humidity Sensing

IEEE Sensors Journal, 2014

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Research paper thumbnail of Interlayer carrier dynamics in underdoped high Tc cuprates

Physica C-superconductivity and Its Applications, Nov 1, 2000

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Research paper thumbnail of Nanoscale Ferroelectrics

Ferroelectric materials possess unique properties such as pyroelectricity and piezoelectricity us... more Ferroelectric materials possess unique properties such as pyroelectricity and piezoelectricity useful for a wide range of technological applications, from non-volatile memories to sensors and actuators. Maintaining the continual rate of miniaturization of such devices presents many challenges, and requires a fundamental understanding of the behaviour of ferroelectrics at nanoscopic scales revealing a fascinating new physics

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Research paper thumbnail of Surface acoustic wave CO<inf>2</inf> sensing with polymer-amino carbon nanotube composites

2008 International Semiconductor Conference, 2008

The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA)... more The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA) and aminocarbon nanotubes, the second on polyethyleneimine (PEI) and aminocarbon nanotubes, are reported. The surface acoustic wave (SAW) sensors, coated with the two selected nanocomposites, showed good sensitivities when varying the CO2 concentrations in the range (500-5000) ppm. The sensor sensitivity is larger when using

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Research paper thumbnail of A Novel High Frequency Surface Acoustic Wave Device Based on Piezoelectric Interdigital Transducers

Integrated Ferroelectrics, 2004

We report on the fabrication of a novel surface acoustic wave device based on piezoelectric inter... more We report on the fabrication of a novel surface acoustic wave device based on piezoelectric interdigital transducers designed in high quality films of Pb(Zr0.2Ti0.8)O3 grown by RF magnetron sputtering. The approach followed is to replace the conventional metallic interdigital transducers by piezoelectric ones consisting of a series of ferroelectric domains with alternating polarization states. The artificial modification of the ferroelectric

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Research paper thumbnail of Crack-free and c-Axis In-plane Aligned Superconducting Y_ Ca_ Ba_2Cu_3O_ Films for Terahertz Radiating Josephson Plasma Devices : Superconductors

Japanese Journal of Applied Physics Pt 1 Regular Papers Short Notes, Nov 15, 2001

ABSTRACT

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Research paper thumbnail of Fabrication of carrier controlled Y1- xCaxBa2Cu3O7-delta films on SrTiO3(100) substrate by pulsed laser deposition

Physica C, 2001

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Research paper thumbnail of Josephson plasma observed in underdoped (110) YBa2Cu3O7-delta films

Appl Phys Lett, 2001

ABSTRACT (110) oriented YBa2Cu3O7-delta thin films have been epitaxially grown on vicinal (110)Sr... more ABSTRACT (110) oriented YBa2Cu3O7-delta thin films have been epitaxially grown on vicinal (110)SrTiO3 substrates by pulsed-laser deposition. Films with different oxygen deficiencies were obtained by annealing under various oxygen ambient. These films have very smooth surface and with their c axis aligned in one direction in the substrate plane. Electronic transport and polarized far-infrared reflectivity measurements reveal the unique features of the c-axis charge dynamics. A c-axis far-infrared reflectivity edge associated with the Josephson plasma in the superconducting state is observed. Our results demonstrate the potential usage of (110) thin films for the investigation of intrinsic interlayer charge dynamics as well as device application of high Tc superconductors.

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Research paper thumbnail of Observation of Josephson plasma in orientation and carrier-controlled YBa 2Cu 3O 7- d films

Physica C, 2001

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Research paper thumbnail of Amino groups-based polymers for CO<inf>2</inf> detection; A comparison between two sensing mechanism models

CAS 2011 Proceedings (2011 International Semiconductor Conference), 2011

Two CO2 sensing mechanisms, based on the Hard Soft Acids Bases (HSAB) and Bronsted-Lowry theories... more Two CO2 sensing mechanisms, based on the Hard Soft Acids Bases (HSAB) and Bronsted-Lowry theories, are discussed and compared. They are evaluated by selecting amino groups-based coating layers, which are deposited on Surface Acoustic Wave (SAW) devices for CO2 detection. Experimentally measured CO2 sensitivities of different coating layers, such as polyallylamine (PAA), polyethyleneimine (PEI), nanocomposite matrix based on PAA-aminocarbon nanotubes and PEI-aminocarbon nanotubes, emeraldine, 4-sulfocalix[4]arene-doped polyaniline, matrix based emeraldine and carbonic anhydrase (PACA) are compared and evaluated according to their corresponding sensing mechanism.

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Research paper thumbnail of A novel piezoelectric interdigital transducer for the excitation of high frequency surface acoustic waves

IEEE Ultrasonics Symposium, 2004, 2004

ABSTRACT

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Research paper thumbnail of Piezoelectric Inter-digital Transducer–PIT–for the Excitation of Guided Acoustic Waves, Ferroelectrics UK

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Research paper thumbnail of Overdoping: a suitable method to get crack-free YBa 2 Cu 3 O 7-δ films

Superconductor Science and Technology, 2001

One of the problems with the c-axis in-plane aligned YBa2Cu3O7-delta films on different substrate... more One of the problems with the c-axis in-plane aligned YBa2Cu3O7-delta films on different substrates is the cracking perpendicular to the c-axis, which should be avoided if such films are to be used for device applications. The devices based on the Josephson plasma phenomenon, which is a phase collective oscillation of the Cooper pair through the insulating barriers of the intrinsic Josephson junctions, requires carrier controlled (Tc = 60 K), c-axis in-plane aligned and crack-free YBa2Cu3O7-delta films. Here we propose that overdoping of the YBa2Cu3O7-delta films by substituting Ca at the Y site can help to produce crack free, c-axis in-plane aligned films. This would help to anneal the YBa2Cu3O7-delta films at a lower oxygen partial pressure than the pristine YBa2Cu3O7-delta and thus to obtain the 60 K phase with an elongated c-axis. This is because substantial oxygen incorporation into the films during annealing followed by the compression of the c-axis are the main causes of the crack formation. We designed an experiment to get crack free, 60 K phase YBa2Cu3O7-delta films with the c-axis in the substrate plane and we verified our design by fabricating c-axis in-plane aligned (110) oriented Y0.7Ca0.3Ba2Cu3O7- y films on SrTiO3 (110) substrates.

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Research paper thumbnail of Fabrication of carrier controlled Y1−xCaxBa2Cu3O7−δ films on SrTiO3() substrate by pulsed laser deposition

Physica C: Superconductivity, 2001

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Research paper thumbnail of c-axis charge dynamics in oxygen deficient YBa2Cu3O7−δ films

Physica C: Superconductivity, 2001

ABSTRACT In-plane c-axis aligned (1 1 0) YBa2Cu3O7−δ thin films on (1 1 0) SrTiO3 substrates have... more ABSTRACT In-plane c-axis aligned (1 1 0) YBa2Cu3O7−δ thin films on (1 1 0) SrTiO3 substrates have been successfully fabricated by pulsed laser deposition, using the self-template method. The oxygen deficiency of the films is controlled in situ by adjusting the annealing oxygen partial pressure PO2. Electronic transport and c-axis far-infrared reflectivity measurements have been conducted on these thin films. It is revealed that in the normal state the carriers are confined in the CuO planes and that their transport across the c-axis is incoherent. A pseudogap develops in the normal state at temperatures well above Tc and it persists in the superconducting state. Upon decreasing the temperature below the critical transition temperature Tc, coherence is built up for the carrier transport along the c-axis and a reflectivity edge associated with the Josephson plasma is observed.

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Research paper thumbnail of Annealing effect on C-doped InGaAs grown by metalorganic chemical vapor deposition

Journal of Crystal Growth, 1998

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Research paper thumbnail of CO2 Sensing Layers for SAW/BAW Devices

SCIENCE AND …, 2011

Abstract. The CO2 sensing performance of several coating layers deposited on piezoelectric device... more Abstract. The CO2 sensing performance of several coating layers deposited on piezoelectric devices (Surface and Bulk Acoustic wave–SAW/BAW) are discussed and compared. The layers are amino groups–based polymers and their selection was based on two principles ...

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Research paper thumbnail of Polymer-Amino Carbon Nanotube Nanocomposites for Surface Acoustic Wave CO2 Detection

SCIENCE AND …, 2009

Abstract. The synthesis of two new types of nanocomposite matrices, the first based on polyallyla... more Abstract. The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA)and amino-carbon nanotubes (amino-CNTs), the second on polyethyleneimine (PEI) and amino-carbon nanotubes, are reported. The surface acoustic wave (SAW) sensors, ...

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Research paper thumbnail of High-frequency surface acoustic wave device based on thin-film piezoelectric interdigital transducers

Applied Physics Letters, 2004

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Research paper thumbnail of CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating

Review of Scientific Instruments, 2013

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Research paper thumbnail of Highly Sensitive Carbon Nanotubes Coated Etched Fiber Bragg Grating Sensor for Humidity Sensing

IEEE Sensors Journal, 2014

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Research paper thumbnail of Interlayer carrier dynamics in underdoped high Tc cuprates

Physica C-superconductivity and Its Applications, Nov 1, 2000

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Research paper thumbnail of Nanoscale Ferroelectrics

Ferroelectric materials possess unique properties such as pyroelectricity and piezoelectricity us... more Ferroelectric materials possess unique properties such as pyroelectricity and piezoelectricity useful for a wide range of technological applications, from non-volatile memories to sensors and actuators. Maintaining the continual rate of miniaturization of such devices presents many challenges, and requires a fundamental understanding of the behaviour of ferroelectrics at nanoscopic scales revealing a fascinating new physics

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Research paper thumbnail of Surface acoustic wave CO<inf>2</inf> sensing with polymer-amino carbon nanotube composites

2008 International Semiconductor Conference, 2008

The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA)... more The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA) and aminocarbon nanotubes, the second on polyethyleneimine (PEI) and aminocarbon nanotubes, are reported. The surface acoustic wave (SAW) sensors, coated with the two selected nanocomposites, showed good sensitivities when varying the CO2 concentrations in the range (500-5000) ppm. The sensor sensitivity is larger when using

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Research paper thumbnail of A Novel High Frequency Surface Acoustic Wave Device Based on Piezoelectric Interdigital Transducers

Integrated Ferroelectrics, 2004

We report on the fabrication of a novel surface acoustic wave device based on piezoelectric inter... more We report on the fabrication of a novel surface acoustic wave device based on piezoelectric interdigital transducers designed in high quality films of Pb(Zr0.2Ti0.8)O3 grown by RF magnetron sputtering. The approach followed is to replace the conventional metallic interdigital transducers by piezoelectric ones consisting of a series of ferroelectric domains with alternating polarization states. The artificial modification of the ferroelectric

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Research paper thumbnail of Crack-free and c-Axis In-plane Aligned Superconducting Y_ Ca_ Ba_2Cu_3O_ Films for Terahertz Radiating Josephson Plasma Devices : Superconductors

Japanese Journal of Applied Physics Pt 1 Regular Papers Short Notes, Nov 15, 2001

ABSTRACT

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Research paper thumbnail of Fabrication of carrier controlled Y1- xCaxBa2Cu3O7-delta films on SrTiO3(100) substrate by pulsed laser deposition

Physica C, 2001

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Research paper thumbnail of Josephson plasma observed in underdoped (110) YBa2Cu3O7-delta films

Appl Phys Lett, 2001

ABSTRACT (110) oriented YBa2Cu3O7-delta thin films have been epitaxially grown on vicinal (110)Sr... more ABSTRACT (110) oriented YBa2Cu3O7-delta thin films have been epitaxially grown on vicinal (110)SrTiO3 substrates by pulsed-laser deposition. Films with different oxygen deficiencies were obtained by annealing under various oxygen ambient. These films have very smooth surface and with their c axis aligned in one direction in the substrate plane. Electronic transport and polarized far-infrared reflectivity measurements reveal the unique features of the c-axis charge dynamics. A c-axis far-infrared reflectivity edge associated with the Josephson plasma in the superconducting state is observed. Our results demonstrate the potential usage of (110) thin films for the investigation of intrinsic interlayer charge dynamics as well as device application of high Tc superconductors.

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Research paper thumbnail of Observation of Josephson plasma in orientation and carrier-controlled YBa 2Cu 3O 7- d films

Physica C, 2001

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Research paper thumbnail of Amino groups-based polymers for CO<inf>2</inf> detection; A comparison between two sensing mechanism models

CAS 2011 Proceedings (2011 International Semiconductor Conference), 2011

Two CO2 sensing mechanisms, based on the Hard Soft Acids Bases (HSAB) and Bronsted-Lowry theories... more Two CO2 sensing mechanisms, based on the Hard Soft Acids Bases (HSAB) and Bronsted-Lowry theories, are discussed and compared. They are evaluated by selecting amino groups-based coating layers, which are deposited on Surface Acoustic Wave (SAW) devices for CO2 detection. Experimentally measured CO2 sensitivities of different coating layers, such as polyallylamine (PAA), polyethyleneimine (PEI), nanocomposite matrix based on PAA-aminocarbon nanotubes and PEI-aminocarbon nanotubes, emeraldine, 4-sulfocalix[4]arene-doped polyaniline, matrix based emeraldine and carbonic anhydrase (PACA) are compared and evaluated according to their corresponding sensing mechanism.

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Research paper thumbnail of A novel piezoelectric interdigital transducer for the excitation of high frequency surface acoustic waves

IEEE Ultrasonics Symposium, 2004, 2004

ABSTRACT

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Research paper thumbnail of Piezoelectric Inter-digital Transducer–PIT–for the Excitation of Guided Acoustic Waves, Ferroelectrics UK

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Research paper thumbnail of Overdoping: a suitable method to get crack-free YBa 2 Cu 3 O 7-δ films

Superconductor Science and Technology, 2001

One of the problems with the c-axis in-plane aligned YBa2Cu3O7-delta films on different substrate... more One of the problems with the c-axis in-plane aligned YBa2Cu3O7-delta films on different substrates is the cracking perpendicular to the c-axis, which should be avoided if such films are to be used for device applications. The devices based on the Josephson plasma phenomenon, which is a phase collective oscillation of the Cooper pair through the insulating barriers of the intrinsic Josephson junctions, requires carrier controlled (Tc = 60 K), c-axis in-plane aligned and crack-free YBa2Cu3O7-delta films. Here we propose that overdoping of the YBa2Cu3O7-delta films by substituting Ca at the Y site can help to produce crack free, c-axis in-plane aligned films. This would help to anneal the YBa2Cu3O7-delta films at a lower oxygen partial pressure than the pristine YBa2Cu3O7-delta and thus to obtain the 60 K phase with an elongated c-axis. This is because substantial oxygen incorporation into the films during annealing followed by the compression of the c-axis are the main causes of the crack formation. We designed an experiment to get crack free, 60 K phase YBa2Cu3O7-delta films with the c-axis in the substrate plane and we verified our design by fabricating c-axis in-plane aligned (110) oriented Y0.7Ca0.3Ba2Cu3O7- y films on SrTiO3 (110) substrates.

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Research paper thumbnail of Fabrication of carrier controlled Y1−xCaxBa2Cu3O7−δ films on SrTiO3() substrate by pulsed laser deposition

Physica C: Superconductivity, 2001

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Research paper thumbnail of c-axis charge dynamics in oxygen deficient YBa2Cu3O7−δ films

Physica C: Superconductivity, 2001

ABSTRACT In-plane c-axis aligned (1 1 0) YBa2Cu3O7−δ thin films on (1 1 0) SrTiO3 substrates have... more ABSTRACT In-plane c-axis aligned (1 1 0) YBa2Cu3O7−δ thin films on (1 1 0) SrTiO3 substrates have been successfully fabricated by pulsed laser deposition, using the self-template method. The oxygen deficiency of the films is controlled in situ by adjusting the annealing oxygen partial pressure PO2. Electronic transport and c-axis far-infrared reflectivity measurements have been conducted on these thin films. It is revealed that in the normal state the carriers are confined in the CuO planes and that their transport across the c-axis is incoherent. A pseudogap develops in the normal state at temperatures well above Tc and it persists in the superconducting state. Upon decreasing the temperature below the critical transition temperature Tc, coherence is built up for the carrier transport along the c-axis and a reflectivity edge associated with the Josephson plasma is observed.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Annealing effect on C-doped InGaAs grown by metalorganic chemical vapor deposition

Journal of Crystal Growth, 1998

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Research paper thumbnail of CO2 Sensing Layers for SAW/BAW Devices

SCIENCE AND …, 2011

Abstract. The CO2 sensing performance of several coating layers deposited on piezoelectric device... more Abstract. The CO2 sensing performance of several coating layers deposited on piezoelectric devices (Surface and Bulk Acoustic wave–SAW/BAW) are discussed and compared. The layers are amino groups–based polymers and their selection was based on two principles ...

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Research paper thumbnail of Polymer-Amino Carbon Nanotube Nanocomposites for Surface Acoustic Wave CO2 Detection

SCIENCE AND …, 2009

Abstract. The synthesis of two new types of nanocomposite matrices, the first based on polyallyla... more Abstract. The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA)and amino-carbon nanotubes (amino-CNTs), the second on polyethyleneimine (PEI) and amino-carbon nanotubes, are reported. The surface acoustic wave (SAW) sensors, ...

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Research paper thumbnail of High-frequency surface acoustic wave device based on thin-film piezoelectric interdigital transducers

Applied Physics Letters, 2004

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Research paper thumbnail of CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating

Review of Scientific Instruments, 2013

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