Synthesis and Characterization of an Ag:Er Alloy for Metallic Magnetic Calorimeters

We synthesized an Ag:Er alloy having paramagnetic properties to be used as a temperature sensor in metallic magnetic calorimeters. The Ag:Er master alloy and a 2-inch target for film deposition were, respectively, manufactured using vacuum arc melting and RF heating under process conditions designed to minimize impurity contamination. Calculations and measurements of magnetization versus magnetic field were employed to check for magnetic impurities in the host material, Ag, and to estimate the Er concentration in the Ag:Er alloy at each step of the synthesis. The temperature-dependent magnetization of deposited thin films from the synthesized Ag:Er with \(^{168}\) $_{}^{168}$ Er isotope was measured in the mK range, demonstrating their suitability as temperature sensors for low-temperature detectors such as metallic magnetic calorimeters.