Development of nano and micro SQUIDs based on Al tunnel junctions

Ishiguro, R.; Watanabe, Eiichiro; Sakuma, Daisuke; Shinozaki, Takahiro; Tsuchiya, Shogo; Nago, Yusuke; Osato, Hirotaka; Tsuya, Daiju; Kashiwaya, Hiromi; Kashiwaya, Satoshi; Nomura, Shintaro; Takayanagi, Hideaki; Maeno, Y.

doi:10.1088/1742-6596/568/2/022019

Cited by 4 publications

(9 citation statements)

References 17 publications

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“…The milled plate was picked up and mounted directly on a micro-SQUID in situ by means of a nano-manipulator system used in our previous study [14]. Figure 3 shows one of the devices.…”

Section: Experimental Devicementioning

confidence: 99%

“…We have so far measured magnetization of a Sr 2 RuO 4 mounted on micro-SQUIDs [11,14]. It is desirable to realize much higher-sensitivity measurements in order to investigate novel vortex states for mesoscopic superconductor [6,7,10].…”

Section: Experimental Devicementioning

confidence: 99%

“…3. These much more careful milling and positioning enables higher-sensitivity magnetization measurements because the SQUID can couple magnetic fluxes around the plate more strongly, compared with experimental devices in previous studies [11,14]. The magnetization measurement device was cooled down to about 40 mK by a dilution cryostat.…”

Section: Experimental Devicementioning

confidence: 99%

“…Figure 1a shows the electron micrograph and the schematics of our typical micro-dc-SQUID. SQUID electrodes are fabricated by electron beam lithography and Aluminum deposition using Dolan-bridge shadow evaporation method [12]: After the pattern is exposed on a silicon substrate spin-coated with the bilayer resist, a first and second Al film with a thickness less than 100 nm is deposited on the angle of plus and minus ten degrees by electron beam physical evaporation, respectively [14]. An insulating film at a Josephson junction is made by oxidation after the first Al deposition.…”

Section: Introductionmentioning

confidence: 99%

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Development of Magnetization Measurement Devices Using Micro-dc-SQUIDs and a Sr$$_2$$RuO$$_4$$ Microplate

et al. 2016

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We developed high-sensitivity magnetization measurement devices composed of micro-dc-SQUIDs and a superconducting Sr 2 RuO 4 microplate, aiming to investigate novel magnetic properties related to a spin-triplet chiral p-wave superconductor with a mesoscopic size. Micron-sized dc-SQUID was fabricated by thin Al electrodes, and the SQUID structure was improved to prevent magnetic fluxes from intruding into SQUID electrodes. A Sr 2 RuO 4 superconducting microplate was fabricated into the size as small as the SQUID loop using a focused ion beam and directly mounted on the SQUID with precise positioning for high-sensitivity magnetization measurements. In the preliminary magnetization measurements of this device, we observed vortices trapped into the plate and thus the lower critical field. The improved magnetization measurement device developed to exclude undesirable flux intrusion successfully enabled high-sensitivity detection of quantized vortex.

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“…The milled plate was picked up and mounted directly on a micro-SQUID in situ by means of a nano-manipulator system used in our previous study [14]. Figure 3 shows one of the devices.…”

Section: Experimental Devicementioning

confidence: 99%

Section: Experimental Devicementioning

confidence: 99%

Section: Experimental Devicementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Development of Magnetization Measurement Devices Using Micro-dc-SQUIDs and a Sr$$_2$$RuO$$_4$$ Microplate

et al. 2016

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“…We have recently fabricated micro-SQUIDs based on Al tunnel-type Josephson junctions using the shadow evaporation technique [10] and investigated magnetic properties of the spin-triplet chiral p-wave superconductor Sr 2 RuO 4 by mounting it directly on the SQUID [11,12]. Such a device enables high-sensitivity magnetization measurements because the SQUID and the material are close to each other.…”

Section: Introductionmentioning

confidence: 99%

Development of a Two-Dimensional Micro-SQUID Array for Investigation of Magnetization Spatial Distribution

et al. 2016

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We developed a two-dimensional array of superconducting quantum interference devices (SQUIDs) for investigation of fine spatial distribution of magnetization in superconducting Sr 2 RuO 4 . Micrometer-sized SQUIDs based on homogeneously formed Al/AlO x /Al tunnel-type Josephson junctions were fabricated using shadow evaporation technique. Unnecessary electrodes formed by the shadow evaporation were removed by inductively coupled plasma reactive ion etching, in order to realize a dense array of SQUIDs. We measured the magnetic modulation of the maximum Josephson current of each SQUID in the array and evaluated the interaction among the SQUIDs.

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Nano Superconducting Quantum Interference device: A powerful tool for nanoscale investigations

2016

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The magnetic sensing at nanoscale level is a promising and interesting research topic of nanoscience. Indeed, magnetic imaging is a powerful tool for probing biological, chemical and physical systems. The study of small spin cluster, like magnetic molecules and nanoparticles, single electron, cold atom clouds, is one of the most stimulating challenges of applied and basic research of the next years. In particular, the magnetic nanoparticle investigation plays a fundamental role for the modern material science and its relative technological applications like ferrofluids, magnetic refrigeration and biomedical applications, including drug delivery, hyper-thermia cancer treatment and magnetic resonance imaging contrast-agent. Actually, one of the most ambitious goals of the high sensitivity magnetometry is the detection of elementary magnetic moment or spin. In this framework, several efforts have been devoted to the development of a high sensitivity magnetic nanosensor pushing sensing capability to the individual spin level. Among the different magnetic sensors, Superconducting QUantum Interference Devices (SQUIDs) exhibit an ultra high sensitivity and are widely employed in numerous applications. Basically, a SQUID consists of a superconducting ring (sensitive area) interrupted by two Josephson junctions. In the recent years, it has been proved that the magnetic response of nano-objects can be effectively measured by using a SQUID with a very small sensitive area (nanoSQUID). In fact, the sensor noise, expressed in terms of the elementary magnetic moment (spin or Bohr magneton), is linearly dependent on the SQUID loop side length. For this reason, SQUIDs have been progressively miniaturized in order to improve the sensitivity up to few spin per unit of bandwidth. With respect to other techniques, nanoSQUIDs offer the advantage of direct measurement of magnetization changes in small spin systems. In this

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Development of nano and micro SQUIDs based on Al tunnel junctions

Cited by 4 publications

References 17 publications

Development of Magnetization Measurement Devices Using Micro-dc-SQUIDs and a Sr$$_2$$RuO$$_4$$ Microplate

Development of Magnetization Measurement Devices Using Micro-dc-SQUIDs and a Sr$$_2$$RuO$$_4$$ Microplate

Development of a Two-Dimensional Micro-SQUID Array for Investigation of Magnetization Spatial Distribution

Nano Superconducting Quantum Interference device: A powerful tool for nanoscale investigations

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