Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 19: Superconductivity: Poster Session
TT 19.48: Poster
Montag, 7. März 2016, 15:00–18:00, Poster D
Microfabricated Thick Proximity Bi-layers as Sensors for Magnetic Penetration Thermometers (MPTs) — •Jeschua Geist, Daniel Hengstler, Andreas Fleischmann, Loredana Gastaldo, Sebastian Kempf, and Christian Enss — Kirchhoff Institute for Physics, Heidelberg University, Germany
Microcalorimeters with inductively coupled temperature sensors like metallic magnetic calorimeters (MMC) are widely used for many applications.Whereas MMCs use dilute paramagnetic alloys as temperature sensors operated at temperatures below 30 mK, magnetic penetration depth thermometers (MPT) make use of the steep temperature dependence of the magnetic penetration depth of a superconducting sensor, potentially offering improved temperature sensitivity at higher and hence easier accessible temperature. Operated below Tc of the sensor material, the temperature change upon the absorption of an X-ray in the detector leads to a change of the magnetic flux density B(r) inside the superconducting sensor and in its vicinity which is detected using a SQUID and serves as a measure of the absorbed energy.
So far we studied the elemental superconductors, Hf, Ir, Ti, Al, Nb, and recently thick proximity bilayers of Al and Au, promising a large range of operational temperatures. We also demonstrated that the penetration of flux lines and the hysteresis of the magnetisation can be engineered by patterning the superconducting sensor layer in form of discs or stripes. We present data on thick bilayers, allowing to tune not only Tc, but also the transition width and therefore the dynamic range, with various geometries and corresponding numerical simulations.