The invention relates to a security feature for securing documents of value, the security feature being based on an ESR active material and a
luminescent material, the ESR active material and the
luminescent material being the same material or different materials, the
luminescent material emitting in the
infrared wavelength region, the ESR active material emitting in the
infrared wavelength region, and the luminescent material emitting in the
infrared wavelength region. The
rare earth metal is based on a main lattice with a garnet structure or a
perovskite structure, and the
rare earth metal content is larger than or equal to 2.0%; -the ESR active material has an ESR active
transition metal; -the ESR active material having a g value lt; 1.9 or gt; the present invention relates to an ESR
signal of 1, 2,..., 2.1, based on a
transition metal-containing host lattice having a garnet structure or a
perovskite structure, having a
transition metal content of an ESR-active transition
metal of > = 5%, and comprising a
rare earth metal, in the case of a garnet structure, the rare earth metal content being > = 2.0% and lt; under the condition of a
perovskite structure, the content of the rare earth metal is greater than or equal to 2.0% and 1t; and 18.0% of the total weight.