Superconducting and electro-optical thin films prepared by pulsed laser deposition technique

Schubert, J.; Siegert, Markus; Fardmanesh, Mehdi; Zander, W.; Prömpers, Michael; Buchal, Ch.; Lisoni, J. G.; Lei, Chang

doi:10.1016/s0169-4332(00)00599-7

Cited by 26 publications

(19 citation statements)

References 14 publications

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“…The of the junctions was highly sensitive to the uniformity of the films and microstructure of the steps, investigated by high resolution SEM [6], [11]. The average of our SEJs decreased as the step heights increased from about 150 nm to about 270 nm.…”

Section: Sej -Characteristics and Magnetic Field Dependencementioning

confidence: 88%

“…The steps were made by making up to 10 m wide ditches onto the substrates. Sharp clean steps with angles close to 90 and flat substrate surfaces at the steps were obtained using an optimized "Combinational IBE" (CIBE) process, the high resolution SEMs of which are reported elsewhere [11]. This was made using a relatively low intensity ( 0.1 mA cm ) and high energy (500-600 eV) stationary 40 angled ion beam along the step edges to reach the approximate desired step height, and using a lower energy ( 300 eV) rotating 45 angled ion beam to get surface modified steps.…”

Section: Sample Preparation and Characterisation Setupmentioning

confidence: 99%

“…High quality films with smooth morphology at the steps could be obtained on LaAlO substrates, with steps prepared using the above CIBE process. The films were deposited by pulsed laser deposition technique using a KrF Excimer laser and patterned using conventional photolithography and IBE techniques [11]. The SQUIDs were made with our typical rf-SQUID magnetometer layout design carrying 100 m by 100 m loop and 3.6 mm diameter washer area [6], [7].…”

Section: Sample Preparation and Characterisation Setupmentioning

confidence: 99%

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Junction characteristics and magnetic field dependencies of low noise step edge junction Rf-SQUIDs for unshielded applications

Fardmanesh

Schubert

Akram

et al. 2003

IEEE Trans. Appl. Supercond.

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Step edge grain boundary (GB) junctions and rf-SQUIDs have been made using pulsed laser deposited Y-Ba-Cu-O films on crystalline LaAlO3 substrates. The steps were developed using various ion-beam etching processes resulting in sharp and ramp type step structures. Sharp step based GB junctions showed behavior of serial junctions with resistively shunted junction (RSJ) -like I-V characteristics. The ramped type step structures resulted in relatively high critical current, Ic, junctions and noisy SQUIDs. The sharp steps resulted in low noise rf-SQUIDs with a noise level below 140 fT/Hz1/2 down to few Hz at 77 K while measured with conventional tank circuits. The Ic of the junctions and hence the operating temperature range of the SQUIDs made using sharp steps was controlled by both the step height and the junction widths. The junction properties of the SQUIDs were also characterized showing RSJ-like characteristics and magnetic field sensitivities correlated to that of the SQUIDs. Two major low and high background magnetic field sensitivities have been observed for our step edge junctions and the SQUIDs made on sharp steps. High quality step edge junctions with low magnetic field sensitivities made on clean sharp steps resulted in low I/f noise rf-SQUIDs proper for applications in unshielded environment

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Section: Sej -Characteristics and Magnetic Field Dependencementioning

confidence: 88%

Section: Sample Preparation and Characterisation Setupmentioning

confidence: 99%

Section: Sample Preparation and Characterisation Setupmentioning

confidence: 99%

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Junction characteristics and magnetic field dependencies of low noise step edge junction Rf-SQUIDs for unshielded applications

Fardmanesh

Schubert

Akram

et al. 2003

IEEE Trans. Appl. Supercond.

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“…The device was patterned to spiral design [7,8]. We deposited an absorber layer over the area of the patterned YBCO thin film.…”

Section: Experimental Results and Analysesmentioning

confidence: 99%

Effect of the nano-structure Cu-carbon composite absorber layer on the response of superconductive YBCO TEBs

Kokabi

Moftakharzadeh

Ghodselahi

et al. 2008

J. Phys.: Conf. Ser.

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Effect of the nano-structure Cu-carbon composite absorber layer on the response of superconductive YBCO TEBs Abstract. We have used a nanostructure copper composite layer as the absorber for infrared radiation on superconductive YBCO bolometers. The Cu composite has the advantage of having little destructive effects on superconductive YBCO material and its deposition process is done at low temperature. The bolometer is made of 200nm thick YBCO film on 1mm thick LaAlO 3 and SrTiO 3 crystalline substrates, deposited using pulsed laser deposition technique. The Cu composite layers were made by decomposition of C 2 H 2 and co sputtering of Cu target in an RF system. The layer was deposited on an insulating buffer layer of diamond like carbon (DLC). The spectral absorption of the Cu composite layer was also measured through measurements of the spectral transmission and reflection of the layer on various substrates. The control of the absorption of the composite layer versus Cu composition has been achieved and presented here. In addition, optimization of the Cu component of the absorber layer for maximum increase of the response of the detectors as well as its effects on the response characteristics of the devices are presented in this paper. IntroductionSuperconductor transition-edge sensors are one of the most sensitive radiation detectors in the range of infrared to far infrared [1,2]. One of the most effective parameters in the sensitivity of these types of detectors is their surface absorption that determines the efficiency of radiation absorption. Typical transition-edge sensors are implemented by thin layer of high-T c superconductor such as YBCO [3]. But due to weak absorption of YBCO material in the IR range [4], these devices typically do not reach their potentially high detectivity values because a little fraction of input power is absorbed by the device when using the bare YBCO film [5]. Therefore, surface coating is essential for increasing infrared response of these devices, particularly in the micrometer wavelength range.One of the major hinders of using absorber layers for the superconducting ETBs is due to their destructive effects on the electrical properties of the superconducting YBCO material. For example, they can cause lowering of the critical temperature T c or smoothening the transition curve. Smoothening and widening transition curve is an undesirable effect, which reduces peak value in dR/dT curves and hence reducing the IR response [6]. In this work, we introduce a novel absorber, which was coated using a low temperature process and had very little destructive effect on our bolometer device. The absorber, used in this work, is a copper-carbon nano-composite that is coated in a low temperature planar magnetron sputtering process, where we have control over the percentage of copper composition in the deposited absorber layer. As we show in this paper, the absorption coefficient of this film is strongly dependent on Cu composition, leading to the control of the absorption coefficient.

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“…A description of the instrument can be found elsewhere [4,11]. The target is a cylinder consisting of stoichiometrical BaTiO 3 powder which had been pressed and sintered.…”

Section: Methodsmentioning

confidence: 99%

Superconducting and electro-optical thin films prepared by pulsed laser deposition technique

Cited by 26 publications

References 14 publications

Junction characteristics and magnetic field dependencies of low noise step edge junction Rf-SQUIDs for unshielded applications

Junction characteristics and magnetic field dependencies of low noise step edge junction Rf-SQUIDs for unshielded applications

Effect of the nano-structure Cu-carbon composite absorber layer on the response of superconductive YBCO TEBs

The growth of BaTiO3 films on (001) MgAl2O4 substrates by pulsed laser deposition technique

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