A BISTABLE SWITCHING DEVICE CONTAINING GADOLINIUM HYDRIDE

A description is given of a switching device 1 comprising a transparent substrate 3, a switching film 5 of gadolinium having a thickness of 200 nm and a palladium layer (7) having a thickness of 10 nm. Under the influence of hydrogen gas, a transparent semiconductive layer (5) of GdH.sub.x (x>2) is formed which can be converted into a non-transparent layer of GdH.sub.x (x<2) by means of evacuation. The conversion between both compositions is reversible, and this phenomenon can for example be used in an optical switching element, a hydrogen sensor and thin displays.