[en] The effects of magnetic interactions on the hard magnetic properties of SmCo₅ ball milled with NiO [antiferromagnetic (AFM) at room temperature] or with CoO [paramagnetic (PM) at room temperature] have been studied. The FM-AFM system exhibits improved magnetic properties (coercivity and squareness) for all compositions. The effects of magnetic interactions on the magnetic properties are analyzed in terms of classical ΔM plots. The plots show that in both systems magnetizing-like FM-FM exchange interactions are predominant for fields μ₀H<μ₀H_C, while long-range dipolar interactions prevail for μ₀H>μ₀H_C. The different types of magnetic interactions are found to depend on the degree of SmCo₅ dispersion in the AFM (NiO) or PM (CoO) matrices. Moreover, the role of the AFM appears to be to enhance both the dipolar and exchange-like interactions, although the exchange effects appear to be responsible for the improvement of the magnetic properties