A sensor assembly for a resistance temperature sensor element includes a substrate and a measuring structure disposed on the substrate. The substrate includes a first material and a stabilized second material. The first material is at least one of aluminum oxide, spinel (magnesium aluminate) and yttrium-aluminum-garnet. The stabilized second material is at least one of stabilized zirconium dioxide and stabilized hafnium dioxide. The stabilized second material is stabilized by containing an oxide of an element having a valence different from four. A coefficient of thermal expansion of the substrate deviates by less than 5% from a coefficient of thermal expansion of the measuring structure.