year | 2020 |
author(s) | Fabian Kaap |
title | Untersuchung des Einflusses von Kernspins und in Niob gespeichertem Wasserstoff auf das niederfrequente magnetische Flussrauschen in supraleitenden Quanteninterferenzdetektoren |
KIP-Nummer | HD-KIP 20-66 |
KIP-Gruppe(n) | F4 |
document type | Masterarbeit |
Abstract (de) | Niederfrequentes magnetisches Flussrauschen beeinflusst die Eigenschaften von Josephson-Kontakt-basierten Bauelementen der supraleitenden Elektronik. Seine Herkunft ist trotz intensiver Bemühungen auf experimenteller und theoretischer Seite bislang nicht vollständig verstanden. Aktuell werden unter anderem Kernspins sowie auf der Oberfläche adsorbierter bzw. im Vollmaterial absorbierter Wasserstoff als mögliche Ursachen diskutiert. Um ersteres zu untersuchen, wurde das niederfrequente Rauschen von SQUIDs, deren SQUID-Schleife aus Aluminium oder Niob besteht, miteinander verglichen. |
Abstract (en) | Low frequency flux noise influences the characteristics of Josephson-junction-based elements in superconducting electronics. Despite an immense effort on the experimental and theoretical side its origin is not completely understood. Currently, nuclear spins as well as hydrogen adsorbed on the surface and absorbed in the bulk, are discussed as possible sources of this noise. To investigate the former, the low frequency noise of SQUIDs, whose SQUID-loops are made of aluminium or niobium, were compared. Therefore, the low frequency noise of twelve dc-SQUID-arrays and two simple SQUID-magnetometers with SQUID-loops made of aluminium was measured. The results are a first indicator that SQUIDs based on aluminium show a lower magnetic flux noise than structurally identical SQUIDs based on niobium and indicate an influence of the nuclear spin on the low frequency magnetic flux noise. To investigate hydrogen as a potential origin of low frequency magnetic flux noise, a method was invented, which enables a controlled storage of hydrogen in a niobium structure using a tank structure. Subsequently, SQUIDs were produced, whose SQUID-loops could be charged with hydrogen post fabrication. The low frequency magnetic flux noise of three of such SQUIDs was measured before and after the hydrogen laoding of the SQUID-loop. The results indicate, that hydrogen stored in niobium results indeed in an increase of low frequency flux noise. |
bibtex | @mastersthesis{Kaap20, author = {Fabian Kaap}, title = {Untersuchung des Einflusses von Kernspins und in Niob gespeichertem Wasserstoff auf das niederfrequente magnetische Flussrauschen in supraleitenden Quanteninterferenzdetektoren}, school = {Universität Heidelberg}, year = {2020}, type = {Masterarbeit} } |