We measured the antiferromagnetic transition temperature T_N in a thin film (25 nm) of Pr_0.5Ca_0.5MnO₃ (PCMO) on SrTiO₃ (STO), which also shows charge and orbital order. The tensile strain was shown earlier to yield a considerable increase of the charge order temperature. Here we measure the spin depolarization rate of low-energy muons, and find that the onset of magnetic order in such a strained film is at the same temperature as T_N of the bulk material, from which we infer that strain has not changed the magnetic order. This is in very good agreement with the general theoretical understanding of the physics of manganites at half-filling.