Abstract Aico Troeman

Recent interest in the development of miniature superconducting quantum interference devices (SQUIDs) has been motivated by the applicability of these sensors for investigations of small, local, magnetic signals, such as the magnetization reversal of small magnetic clusters deposited inside the SQUID washer and the observation of local magnetic structures using a scanning SQUID microscope (SSM). In the first part of this thesis the realization of miniature SQUIDs, based on Niobium nanobridges produced by focused ion beam milling (FIB), with effective areas as small as 3.6 x 10^-4 mm² is described. From a fabrication point of view the realization of such devices offers less practical limitations compared to the implementation of miniature sensors based on “classical” Josephson tunnel junctions. The described results offer a significant step forward in the nano-fabrication of SQUIDs. Furthermore, based on measurements of the supercurrent-phase relationship in Niobium nanobridges, valuable insight in the physical mechanisms determining the electronic properties of realized SQUIDs is acquired.

In the second part of the thesis experiments on SSM systems and sensors are described. By nano-patterning the pick-up loops of conventional SSM sensors by means of FIB milling, the effective area during operation is significantly reduced. The operation of such sensors in two SSM systems is showcased. The first system, developed at IBM Yorktown Heights, NY, USA, is based on the translation of the scanning motion, which is generated outside of the cryostat by linear actuators, into the cryogenic environment. The second system, developed at the University of Twente, is based on a low temperature piezo scanning stage. Based on the highly accurate scanning motion produced by such piezo modules, the latter system offers perspectives for the application of future nano-sized SSM sensors.

	Home > ... > summary's > Abstract Aico Troeman
Home News Events Strategic Orientations research groups Publications PhD students Education MESA+ NanoLab Starting entrepreneurs Tech Park Industrial Partners Vacancies Links Sitemap Search	Abstract Aico Troeman Recent interest in the development of miniature superconducting quantum interference devices (SQUIDs) has been motivated by the applicability of these sensors for investigations of small, local, magnetic signals, such as the magnetization reversal of small magnetic clusters deposited inside the SQUID washer and the observation of local magnetic structures using a scanning SQUID microscope (SSM). In the first part of this thesis the realization of miniature SQUIDs, based on Niobium nanobridges produced by focused ion beam milling (FIB), with effective areas as small as 3.6 x 10^-4 mm² is described. From a fabrication point of view the realization of such devices offers less practical limitations compared to the implementation of miniature sensors based on “classical” Josephson tunnel junctions. The described results offer a significant step forward in the nano-fabrication of SQUIDs. Furthermore, based on measurements of the supercurrent-phase relationship in Niobium nanobridges, valuable insight in the physical mechanisms determining the electronic properties of realized SQUIDs is acquired. In the second part of the thesis experiments on SSM systems and sensors are described. By nano-patterning the pick-up loops of conventional SSM sensors by means of FIB milling, the effective area during operation is significantly reduced. The operation of such sensors in two SSM systems is showcased. The first system, developed at IBM Yorktown Heights, NY, USA, is based on the translation of the scanning motion, which is generated outside of the cryostat by linear actuators, into the cryogenic environment. The second system, developed at the University of Twente, is based on a low temperature piezo scanning stage. Based on the highly accurate scanning motion produced by such piezo modules, the latter system offers perspectives for the application of future nano-sized SSM sensors.