Interfacial modulation of magnetic relaxation and electrical characteristic in RuO2/CrO2 antiferromagnet-half metal bilayer

•The magnetic relaxation of CrO2 film is significantly enhanced by the antiferromagnetic RuO2 layer.•The magnetic damping of CrO2 film can be strongly modulated via the interfacial effect from the neighboring RuO2 layer.•The CrO2 films epitaxially grown on RuO2 layer exhibit a perfect in-plane magnetic uniaxial anisotropy.•Intergrain tunnelling magnetoresistance and double-exchange mechanism leads to a linear magnetoresistance in CrO2 film.