The invention concerns a microbolometer comprising a suspended part containing radiation-sensitive elements and consisting of a set of first zones and a set of second zones, the two sets being superimposed; furthermore, the materials constituting said zones and have thermal expansion coefficients sufficiently different for said suspended part to be deformed under the effect of a rise in temperature to be urged into contact with the substrate when the contact zone reaches a temperature Tc less than the destruction temperature Td of the microbolometer. The invention is applicable to radiation detectors comprising an assembly of such microbolometers, and to various appliances comprising at least such a radiation detector.