Development of Thin Film PdMn High Resolution Thermometry for Measurement of the He-4 Superfluid Boundary Layer and Other Applications

摘要

This thesis describes the development of PdMn thin films for high resolution thermometry. Measurements of the magnetic sensitivity of sputtered thin films of PdMn alloy suggest that the sputtering technique produces an ordered film with a manganese concentration slightly higher than the nominal value of the sputtering target. Sputtering from a 0.68% manganese target produced films with a concentration of approximately 0.90%, as judged by comparison with results from bulk PdMn sensitivity measurements. The thinnest films show significant domain scale noise below the Curie Temperature, Tc, while thicker films show reliable non-hysteretic behavior throughout the temperature range of interest. These films will serve as the thermometric element in a new class of bolometers for fundamental physics applications. They may also prove useful as a new class of conventional, low-temperature thermometers. Furthermore, measurements made at very low fields suggest that these films may be useful in a new class of biomagnetic measurements.