Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference devic... more Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference device (rf-SQUID) meta-atom is explored via intermodulation (IM) measurements. Previous work in zero dc magnetic flux showed a sharp onset of IM response as the frequency sweeps through the resonance. A second onset at higher frequency was also observed, creating a prominent gap in the IM response. By extending those measurements to nonzero dc flux, new dynamics are revealed, including: dc flux tunabililty of the aforementioned gaps, and enhanced IM response near geometric resonance of the rf-SQUID. These features observed experimentally are understood and analyzed theoretically through a combination of a steady state analytical modeling, and a full numerical treatment of the rf SQUID dynamics. The latter, in addition, predicts the presence of chaos in narrow parameter regimes. The understanding of intermodulation in rf-SQUID metamaterials is important for producing low-noise amplification of microwave signals and tunable filters.
Superconducting resonators are widely used in many applications such as qubit readout for quantum... more Superconducting resonators are widely used in many applications such as qubit readout for quantum computing, and kinetic inductance detectors. These resonators are susceptible to numerous loss and noise mechanisms, especially the dissipation due to two-level systems (TLS) which become the dominant source of loss in the few-photon and low temperature regime. In this study, capacitively-coupled aluminum half-wavelength coplanar waveguide resonators are investigated. Surprisingly, the loss of the resonators was observed to decrease with a lowering temperature at low excitation powers and temperatures below the TLS saturation. This behavior is attributed to the reduction of the TLS resonant response bandwidth with decreasing temperature and power to below the detuning between the TLS and the resonant photon frequency in a discrete ensemble of TLS. When response bandwidths of TLS are smaller than their detunings from the resonance, the resonant response and thus the loss is reduced. At higher excitation powers, the loss follows a logarithmic power dependence, consistent with predictions from the generalized tunneling model (GTM). A model combining the discrete TLS ensemble with the GTM is proposed and matches the temperature and power dependence of the measured internal loss of the resonator with reasonable parameters.
Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference devic... more Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference device (rf-SQUID) meta-atom is explored via intermodulation (IM) measurements. Previous work in zero dc magnetic flux showed a sharp onset of IM response as the frequency sweeps through the resonance. A second onset at higher frequency was also observed, creating a prominent gap in the IM response. By extending those measurements to nonzero dc flux, new dynamics are revealed, including: dc flux tunabililty of the aforementioned gaps, and enhanced IM response near geometric resonance of the rf-SQUID. These features observed experimentally are understood and analyzed theoretically through a combination of a steady state analytical modeling, and a full numerical treatment of the rf SQUID dynamics. The latter, in addition, predicts the presence of chaos in narrow parameter regimes. The understanding of intermodulation in rf-SQUID metamaterials is important for producing low-noise amplification of...
Localized high frequency (several GHz) electrodynamic pro pe ties of a high quality epitaxial, si... more Localized high frequency (several GHz) electrodynamic pro pe ties of a high quality epitaxial, single-crystal Iron-Pnicitde Ba(Fe 1−xCox)2As2 thin film near optimal doping (x=0.08) are measured under a lo c lized and strong RF magnetic field, created by a near-field microwave mi croscope. Two reflection electrodynamic measurements, including linear and the third harmonic respons es, are performed to understand the electromagnetic properties of Ba(Fe 1−xCox)2As2. Our measurement results show that Ba(Fe 1−xCox)2As2 has have a wide superconducting transition width and may have a multi-gap nat ure. In addition, based on the 1 /T 2 dependence of the third harmonics signal at lower temperature, Ba(Fe 1−xCox)2As2 shows the possibility of nodal behavior.
Frequency (SRF) cavities are being widely used in new generation particle accelerators. These SRF... more Frequency (SRF) cavities are being widely used in new generation particle accelerators. These SRF cavities are based on bulk Nb. Based on the needs of the SRF community to identify defects on Nb surfaces, a novel near-field magnetic microwave microscope was successfully built using a magnetic writer from a conventional magnetic recording hard-disk drive1. This magnetic writer can create an RF magnetic field, localized and strong enough to drive Nb into the vortex state. This probe enables us to locate defects through scanning and mapping of the local electrodynamic response in the multi-GHz frequency range. Recent measurements have shown that 3rd harmonic nonlinear response is far more sensitive to variations in input power and temperature then linear response, thus we mainly study the 3rd harmonic response. Moreover, the superconductor is usually the only source for nonlinear response in our setup, thus there is less chance of having noise or background signal. Understanding the mechanism responsible for this non-linear response is important for improving the performance of SRF cavities. Besides Nb we also study various other superconductors such as MgB2 and the cuprate Bi-Sr-Ca-Cu-O (BSCCO) for potential applications in SRF cavities.
Superconducting resonators are widely used in many applications such as qubit readout for quantum... more Superconducting resonators are widely used in many applications such as qubit readout for quantum computing applications, and kinetic inductance detectors. These resonators are susceptible to numerous loss and noise mechanisms under microwave excitation, especially the dissipation due to non-equilibrium quasi-particles and two-level systems (TLS), which can result in a decrease of the superconducting intrinsic quality factor (Qi) in high quality superconducting resonators. Particularly in the few-photon and low temperature (T ) regime, TLS losses can become a dominant loss mechanism. In this study, novel aluminum half-wavelength resonators are investigated, focusing on the loss properties at extra-low power and low temperature. An unusual increase of Qi(T ) with deceasing temperature is observed. This behavior is attributed to the increase of TLS coherence time (T2) at ultra-low temperatures and powers. This T2 increase is consistent with other work on resonant frequency noise in re...
Title of dissertation: Measuring Electromagnetic Properties of Superconductors in High and Locali... more Title of dissertation: Measuring Electromagnetic Properties of Superconductors in High and Localized RF Magnetic Field Tamin Tai, Doctor of Philosophy, 2013 Dissertation directed by: Professor Steven M. Anlage Department of Electrical and Computer Engineering Niobium-based Superconducting Radio Frequency (SRF) particle accelerator cavity performance is sensitive to localized defects that give rise to quenches at high accelerating gradients. In order to identify these material defects on bulk Nb surfaces at their operating frequency and temperature, it is important to develop a new kind of wide bandwidth microwave microscopy with localized and strong RF magnetic fields. A novel near-field magnetic field microwave microscope that enables mapping of the local electrodynamic response in the multi-GHz frequency regime at liquid helium cryogenic temperatures was successfully built via the combination of a magnetic writer and a near field-microwave microscope 1 . This magnetic writer can c...
Physica C: Superconductivity and its Applications, 2017
Ba(Fe 1-x Co x) 2 As 2 Superconductivity Microwave frequency measurement Niobium a b s t r a c t ... more Ba(Fe 1-x Co x) 2 As 2 Superconductivity Microwave frequency measurement Niobium a b s t r a c t High frequency (several GHz) electrodynamic properties of a high-quality epitaxial, single-crystal Iron-Pnictide Ba(Fe 1 −x Co x) 2 As 2 thin film near optimal doping (x = 0.08) are measured under a localized and strong RF magnetic field created by a near-field microwave microscope. Linear response and third harmonic electrodynamic measurements are performed to understand the electromagnetic properties of Ba(Fe 1 −x Co x) 2 As 2 and contrasts are drawn with similar measurements on Nb. Our measurement results show that Ba(Fe 1 −x Co x) 2 As 2 has nonlinear response potentially arising from a number of mechanisms and may show evidence of a multi-gap nature.
The performance of Niobium-based Superconducting Radio Frequency (SRF) particle accelerator cavit... more The performance of Niobium-based Superconducting Radio Frequency (SRF) particle accelerator cavities can be sensitive to localized defects that give rise to quenches at high accelerating gradients. In order to identify these material defects on bulk Nb surfaces at their operating frequency and temperature, a wide bandwidth microwave microscope with localized and strong RF magnetic fields is developed by integrating a magnetic write head into the near-field microwave microscope to enable mapping of the local electrodynamic response in the multi-GHz frequency regime at cryogenic temperatures. This magnetic writer demonstrates a localized and strong RF magnetic field on bulk Nb surface with B sur f ace > 10 2 mT and sub-micron resolution. By measuring the nonlinear response of the superconductor, nonlinearity coming from the nano-scale weak link Josephson junctions due to the contaminated surface in the cavity fabrication process is demonstrated.
Rapid communications in mass spectrometry : RCM, Jan 11, 2017
As the spatial resolution of mass spectrometry imaging technologies has begun to reach into the n... more As the spatial resolution of mass spectrometry imaging technologies has begun to reach into the nanometer regime, finding readily available or easily made resolution reference materials has become particularly challenging for molecular imaging purposes. This paper describes the fabrication, characterization and use of vertical line array polymeric spatial resolution test patterns for nano-thermal analysis/atomic force microscopy/mass spectrometry chemical imaging. Test patterns of varied line width (0.7 or 1.0 μm) and spacing (0.7 or 1.0 μm) were created in an ~1-μm-thick poly(methyl methacrylate) thin film using electron beam lithography. The patterns were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy topography and nano-thermal analysis/mass spectrometry imaging. The efficacy of these polymeric test patterns for the advancement of chemical imaging technique was illustrated by their use to judge the spatial resolution i...
2007 Conference on Lasers and Electro-Optics - Pacific Rim, 2007
ABSTRACT Periodically poled lithium niobate crystal fiber (PPLNCF) has great potential to be used... more ABSTRACT Periodically poled lithium niobate crystal fiber (PPLNCF) has great potential to be used as tunable blue/green light source as well as wavelength converter in optical communications. Using the laser-heated pedestal growth method, PPLNCF was fabricated by an in-situ electric-field induced micro-swing poling technique. Its growth, cladding, and optical characterization will be discussed.
In this paper, the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometr... more In this paper, the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometry imaging platform was demonstrated for the acquisition and correlation of nanoscale sample surface topography and chemical images based on infrared spectroscopy and mass spectrometry. The infrared chemical imaging component of the system utilized photothermal expansion of the sample at the tip of the atomic force microscopy probe recorded at infrared wave numbers specific to the different surface constituents. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for thermolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. The basic instrumental setup, operation, and image correlation procedures are discussed, and the multimodal imaging capability and utility are demonstrated using a phase separated poly(2-vinylpyridine)/poly(methyl methacrylate) ...
Localized high frequency (several GHz) electrodynamic properties of a high quality epitaxial, sin... more Localized high frequency (several GHz) electrodynamic properties of a high quality epitaxial, single-crystal Iron-Pnicitde Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ thin film near optimal doping (x=0.08) are measured under a localized and strong RF magnetic field, created by a near-field microwave microscope. Two reflection electrodynamic measurements, including linear and the third harmonic responses, are performed to understand the electromagnetic properties of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$. Our measurement results show that Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ has have a wide superconducting transition width and may have a multi-gap nature. In addition, based on the $1/T^2$ dependence of the third harmonics signal at lower temperature, Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ shows the possibility of nodal behavior.
The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrat... more The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrating the co-registered topographical, band excitation nanomechanical, and mass spectral imaging of a surface using a single instrument is reported. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for pyrolytic surface sampling followed by atmospheric pressure chemical ionization of the gas-phase species produced with subsequent mass analysis. The basic instrumental setup and operation are discussed, and the multimodal imaging capability and utility are demonstrated using a phase-separated polystyrene/poly(2-vinylpyridine) polymer blend thin film. The topography and band excitation images showed that the valley and plateau regions of the thin film surface were comprised primarily of one of the two polymers in the blend with the mass spectral chemical image used to definitively identify the polymers at the different locations. Data p...
Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference devic... more Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference device (rf-SQUID) meta-atom is explored via intermodulation (IM) measurements. Previous work in zero dc magnetic flux showed a sharp onset of IM response as the frequency sweeps through the resonance. A second onset at higher frequency was also observed, creating a prominent gap in the IM response. By extending those measurements to nonzero dc flux, new dynamics are revealed, including: dc flux tunabililty of the aforementioned gaps, and enhanced IM response near geometric resonance of the rf-SQUID. These features observed experimentally are understood and analyzed theoretically through a combination of a steady state analytical modeling, and a full numerical treatment of the rf SQUID dynamics. The latter, in addition, predicts the presence of chaos in narrow parameter regimes. The understanding of intermodulation in rf-SQUID metamaterials is important for producing low-noise amplification of microwave signals and tunable filters.
Superconducting resonators are widely used in many applications such as qubit readout for quantum... more Superconducting resonators are widely used in many applications such as qubit readout for quantum computing, and kinetic inductance detectors. These resonators are susceptible to numerous loss and noise mechanisms, especially the dissipation due to two-level systems (TLS) which become the dominant source of loss in the few-photon and low temperature regime. In this study, capacitively-coupled aluminum half-wavelength coplanar waveguide resonators are investigated. Surprisingly, the loss of the resonators was observed to decrease with a lowering temperature at low excitation powers and temperatures below the TLS saturation. This behavior is attributed to the reduction of the TLS resonant response bandwidth with decreasing temperature and power to below the detuning between the TLS and the resonant photon frequency in a discrete ensemble of TLS. When response bandwidths of TLS are smaller than their detunings from the resonance, the resonant response and thus the loss is reduced. At higher excitation powers, the loss follows a logarithmic power dependence, consistent with predictions from the generalized tunneling model (GTM). A model combining the discrete TLS ensemble with the GTM is proposed and matches the temperature and power dependence of the measured internal loss of the resonator with reasonable parameters.
Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference devic... more Strong nonlinearity of a self-resonant radio frequency superconducting quantum interference device (rf-SQUID) meta-atom is explored via intermodulation (IM) measurements. Previous work in zero dc magnetic flux showed a sharp onset of IM response as the frequency sweeps through the resonance. A second onset at higher frequency was also observed, creating a prominent gap in the IM response. By extending those measurements to nonzero dc flux, new dynamics are revealed, including: dc flux tunabililty of the aforementioned gaps, and enhanced IM response near geometric resonance of the rf-SQUID. These features observed experimentally are understood and analyzed theoretically through a combination of a steady state analytical modeling, and a full numerical treatment of the rf SQUID dynamics. The latter, in addition, predicts the presence of chaos in narrow parameter regimes. The understanding of intermodulation in rf-SQUID metamaterials is important for producing low-noise amplification of...
Localized high frequency (several GHz) electrodynamic pro pe ties of a high quality epitaxial, si... more Localized high frequency (several GHz) electrodynamic pro pe ties of a high quality epitaxial, single-crystal Iron-Pnicitde Ba(Fe 1−xCox)2As2 thin film near optimal doping (x=0.08) are measured under a lo c lized and strong RF magnetic field, created by a near-field microwave mi croscope. Two reflection electrodynamic measurements, including linear and the third harmonic respons es, are performed to understand the electromagnetic properties of Ba(Fe 1−xCox)2As2. Our measurement results show that Ba(Fe 1−xCox)2As2 has have a wide superconducting transition width and may have a multi-gap nat ure. In addition, based on the 1 /T 2 dependence of the third harmonics signal at lower temperature, Ba(Fe 1−xCox)2As2 shows the possibility of nodal behavior.
Frequency (SRF) cavities are being widely used in new generation particle accelerators. These SRF... more Frequency (SRF) cavities are being widely used in new generation particle accelerators. These SRF cavities are based on bulk Nb. Based on the needs of the SRF community to identify defects on Nb surfaces, a novel near-field magnetic microwave microscope was successfully built using a magnetic writer from a conventional magnetic recording hard-disk drive1. This magnetic writer can create an RF magnetic field, localized and strong enough to drive Nb into the vortex state. This probe enables us to locate defects through scanning and mapping of the local electrodynamic response in the multi-GHz frequency range. Recent measurements have shown that 3rd harmonic nonlinear response is far more sensitive to variations in input power and temperature then linear response, thus we mainly study the 3rd harmonic response. Moreover, the superconductor is usually the only source for nonlinear response in our setup, thus there is less chance of having noise or background signal. Understanding the mechanism responsible for this non-linear response is important for improving the performance of SRF cavities. Besides Nb we also study various other superconductors such as MgB2 and the cuprate Bi-Sr-Ca-Cu-O (BSCCO) for potential applications in SRF cavities.
Superconducting resonators are widely used in many applications such as qubit readout for quantum... more Superconducting resonators are widely used in many applications such as qubit readout for quantum computing applications, and kinetic inductance detectors. These resonators are susceptible to numerous loss and noise mechanisms under microwave excitation, especially the dissipation due to non-equilibrium quasi-particles and two-level systems (TLS), which can result in a decrease of the superconducting intrinsic quality factor (Qi) in high quality superconducting resonators. Particularly in the few-photon and low temperature (T ) regime, TLS losses can become a dominant loss mechanism. In this study, novel aluminum half-wavelength resonators are investigated, focusing on the loss properties at extra-low power and low temperature. An unusual increase of Qi(T ) with deceasing temperature is observed. This behavior is attributed to the increase of TLS coherence time (T2) at ultra-low temperatures and powers. This T2 increase is consistent with other work on resonant frequency noise in re...
Title of dissertation: Measuring Electromagnetic Properties of Superconductors in High and Locali... more Title of dissertation: Measuring Electromagnetic Properties of Superconductors in High and Localized RF Magnetic Field Tamin Tai, Doctor of Philosophy, 2013 Dissertation directed by: Professor Steven M. Anlage Department of Electrical and Computer Engineering Niobium-based Superconducting Radio Frequency (SRF) particle accelerator cavity performance is sensitive to localized defects that give rise to quenches at high accelerating gradients. In order to identify these material defects on bulk Nb surfaces at their operating frequency and temperature, it is important to develop a new kind of wide bandwidth microwave microscopy with localized and strong RF magnetic fields. A novel near-field magnetic field microwave microscope that enables mapping of the local electrodynamic response in the multi-GHz frequency regime at liquid helium cryogenic temperatures was successfully built via the combination of a magnetic writer and a near field-microwave microscope 1 . This magnetic writer can c...
Physica C: Superconductivity and its Applications, 2017
Ba(Fe 1-x Co x) 2 As 2 Superconductivity Microwave frequency measurement Niobium a b s t r a c t ... more Ba(Fe 1-x Co x) 2 As 2 Superconductivity Microwave frequency measurement Niobium a b s t r a c t High frequency (several GHz) electrodynamic properties of a high-quality epitaxial, single-crystal Iron-Pnictide Ba(Fe 1 −x Co x) 2 As 2 thin film near optimal doping (x = 0.08) are measured under a localized and strong RF magnetic field created by a near-field microwave microscope. Linear response and third harmonic electrodynamic measurements are performed to understand the electromagnetic properties of Ba(Fe 1 −x Co x) 2 As 2 and contrasts are drawn with similar measurements on Nb. Our measurement results show that Ba(Fe 1 −x Co x) 2 As 2 has nonlinear response potentially arising from a number of mechanisms and may show evidence of a multi-gap nature.
The performance of Niobium-based Superconducting Radio Frequency (SRF) particle accelerator cavit... more The performance of Niobium-based Superconducting Radio Frequency (SRF) particle accelerator cavities can be sensitive to localized defects that give rise to quenches at high accelerating gradients. In order to identify these material defects on bulk Nb surfaces at their operating frequency and temperature, a wide bandwidth microwave microscope with localized and strong RF magnetic fields is developed by integrating a magnetic write head into the near-field microwave microscope to enable mapping of the local electrodynamic response in the multi-GHz frequency regime at cryogenic temperatures. This magnetic writer demonstrates a localized and strong RF magnetic field on bulk Nb surface with B sur f ace > 10 2 mT and sub-micron resolution. By measuring the nonlinear response of the superconductor, nonlinearity coming from the nano-scale weak link Josephson junctions due to the contaminated surface in the cavity fabrication process is demonstrated.
Rapid communications in mass spectrometry : RCM, Jan 11, 2017
As the spatial resolution of mass spectrometry imaging technologies has begun to reach into the n... more As the spatial resolution of mass spectrometry imaging technologies has begun to reach into the nanometer regime, finding readily available or easily made resolution reference materials has become particularly challenging for molecular imaging purposes. This paper describes the fabrication, characterization and use of vertical line array polymeric spatial resolution test patterns for nano-thermal analysis/atomic force microscopy/mass spectrometry chemical imaging. Test patterns of varied line width (0.7 or 1.0 μm) and spacing (0.7 or 1.0 μm) were created in an ~1-μm-thick poly(methyl methacrylate) thin film using electron beam lithography. The patterns were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy topography and nano-thermal analysis/mass spectrometry imaging. The efficacy of these polymeric test patterns for the advancement of chemical imaging technique was illustrated by their use to judge the spatial resolution i...
2007 Conference on Lasers and Electro-Optics - Pacific Rim, 2007
ABSTRACT Periodically poled lithium niobate crystal fiber (PPLNCF) has great potential to be used... more ABSTRACT Periodically poled lithium niobate crystal fiber (PPLNCF) has great potential to be used as tunable blue/green light source as well as wavelength converter in optical communications. Using the laser-heated pedestal growth method, PPLNCF was fabricated by an in-situ electric-field induced micro-swing poling technique. Its growth, cladding, and optical characterization will be discussed.
In this paper, the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometr... more In this paper, the use of a hybrid atomic force microscopy/infrared spectroscopy/mass spectrometry imaging platform was demonstrated for the acquisition and correlation of nanoscale sample surface topography and chemical images based on infrared spectroscopy and mass spectrometry. The infrared chemical imaging component of the system utilized photothermal expansion of the sample at the tip of the atomic force microscopy probe recorded at infrared wave numbers specific to the different surface constituents. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for thermolytic surface sampling followed by atmospheric pressure chemical ionization of the gas phase species produced with subsequent mass analysis. The basic instrumental setup, operation, and image correlation procedures are discussed, and the multimodal imaging capability and utility are demonstrated using a phase separated poly(2-vinylpyridine)/poly(methyl methacrylate) ...
Localized high frequency (several GHz) electrodynamic properties of a high quality epitaxial, sin... more Localized high frequency (several GHz) electrodynamic properties of a high quality epitaxial, single-crystal Iron-Pnicitde Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ thin film near optimal doping (x=0.08) are measured under a localized and strong RF magnetic field, created by a near-field microwave microscope. Two reflection electrodynamic measurements, including linear and the third harmonic responses, are performed to understand the electromagnetic properties of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$. Our measurement results show that Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ has have a wide superconducting transition width and may have a multi-gap nature. In addition, based on the $1/T^2$ dependence of the third harmonics signal at lower temperature, Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ shows the possibility of nodal behavior.
The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrat... more The advancement of a hybrid atomic force microscopy/mass spectrometry imaging platform demonstrating the co-registered topographical, band excitation nanomechanical, and mass spectral imaging of a surface using a single instrument is reported. The mass spectrometry-based chemical imaging component of the system utilized nanothermal analysis probes for pyrolytic surface sampling followed by atmospheric pressure chemical ionization of the gas-phase species produced with subsequent mass analysis. The basic instrumental setup and operation are discussed, and the multimodal imaging capability and utility are demonstrated using a phase-separated polystyrene/poly(2-vinylpyridine) polymer blend thin film. The topography and band excitation images showed that the valley and plateau regions of the thin film surface were comprised primarily of one of the two polymers in the blend with the mass spectral chemical image used to definitively identify the polymers at the different locations. Data p...
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