CRITICAL CURRENT DEPENDENCE OF STACKED JOSEPHSON JUNCTIONS DC SQUID IN Bi2Sr2CaCu2O8+Δ

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3270-3273 ◽  
Author(s):  
SANG-JAE KIM
Keyword(s):  
Magnetic Fields ◽  
Critical Current ◽  
Josephson Junctions ◽  
Quantum Interference ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Periodic Modulation ◽  
Superconducting Quantum Interference Device ◽  
Current Dependence ◽  
Loop Area

We investigate critical current (Ic) modulation of stacked Josephson junctions (SJJs) dc superconducting quantum interference device ( dc SQUID) on a Bi 2 Sr 2 CaCu 2 O 8+δ ( Bi -2212) whisker. A coupled SJJs with a completely perforated hole of 0.1 μ m × 0.2 μ m were fabricated by using a 3-D focused-ion-beam (FIB) etching method. Those dc SQUIDs exhibited uniform multi-branch structures and clearly oscillated critical current under external magnetic fields (He). With applying He, the clear periodic modulation patterns of Ic are obtained and well fitted to the calculated value from the loop area of 0.02 μm2.

TRANSPORT CHARACTERISTICS IN c-AXIS La2-xSrxCuO4 (LSCO) SINGLE CRYSTALS

2005 ◽  
Vol 19 (01n03) ◽  
pp. 447-450
Author(s):  
SANG-JAE KIM ◽  
TAKESHI HATANO
Keyword(s):  
Temperature Dependence ◽  
Single Crystals ◽  
Critical Current ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Etching Method ◽  
First Time ◽  
Small Voltage

c-axis micro-bridges of La 2-x Sr x CuO 4 ( LSCO ) single crystals were fabricated by the focused-ion-beam (FIB) etching method. Small rectangular LSCO pieces were fabricated by cutting and grinding single crystals of underdoped LSCO of x=0.09. The size of LSCO single crystals between electrodes was cut to 20×40μm2 in ab-plane by using the FIB etching method. Superconductor-insulator-superconductor (SIS) like-branch structures on I-V curves of the LSCO stacks were observed for the first time. The branch structures exhibited voltage jumps of several tens mV in the range of from 1.7 K to 5 K with temperature dependence. When the temperature is changed from 5 K to 1.7 K , the critical current and the next branch split into a few of small voltage jumps with the intervals of several mV in the range of from 0.1 mV and 2.0 mV .

PLANAR JOSEPHSON JUNCTIONS FABRICATED BY FOCUSED-ION BEAM

2001 ◽  
Vol 15 (24n25) ◽  
pp. 3359-3360 ◽  
Author(s):  
Hye-Won Seo ◽  
Quark Y. Chen ◽  
Chong Wang ◽  
Wei-Kan Chu ◽  
T. M. Chuang ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Josephson Junctions ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Spot Size ◽  
Physical Significance ◽  
Fabrication Technique ◽  
Beam Spot ◽  
Beam Spot Size ◽  
Current Voltage

We have fabricated nano-scaled planar superconductor-insulator-superconductor Josephson junctions using focused ion beam (FIB) with beam spot size ~5 nm . To study the effectiveness of this fabrication technique and for the purpose of comparisons, a variety of samples have been made based on high temperature superconducting (HTS) YBa2Cu3O7-δ electrodes. The insulators are either vacuum or silicon dioxide. The samples showed current-voltage (IV) characteristics typical of a resistively shunted junction (RSJ). We will discuss various aspects of the processing methods and the physical significance of the junction characteristics.

scholarly journals Thickness-modulated tungsten–carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields

2016 ◽  
Vol 7 ◽  
pp. 1698-1708 ◽  
Author(s):  
Ismael García Serrano ◽  
Javier Sesé ◽  
Isabel Guillamón ◽  
Hermann Suderow ◽  
Sebastián Vieira ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Focused Ion Beam ◽  
Vortex Lattice ◽  
Ion Beam ◽  
Electrical Current ◽  
Single Step ◽  
Vortex Pinning ◽  
High Magnetic Fields ◽  
Pinning Potential ◽  
External Stimuli

We report efficient vortex pinning in thickness-modulated tungsten–carbon-based (W–C) nanostructures grown by focused ion beam induced deposition (FIBID). By using FIBID, W–C superconducting films have been created with thickness modulation properties exhibiting periodicity from 60 to 140 nm, leading to a strong pinning potential for the vortex lattice. This produces local minima in the resistivity up to high magnetic fields (2.2 T) in a broad temperature range due to commensurability effects between the pinning potential and the vortex lattice. The results show that the combination of single-step FIBID fabrication of superconducting nanostructures with built-in artificial pinning landscapes and the small intrinsic random pinning potential of this material produces strong periodic pinning potentials, maximizing the opportunities for the investigation of fundamental aspects in vortex science under changing external stimuli (e.g., temperature, magnetic field, electrical current).

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