The magnetic, grain morphology and dielectric properties of synthesized Sr₂MnNiFe₁₂O₂₂+xY₂O₃ (x=0-5wt.%) ferrite have been investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM) and dielectric spectroscopy, respectively. The nanostructure governs increase in inter-grain connectivity with substitution. The appearance of broad peaks in imaginary electric modulus plots (Mʺ) show the existence of relaxation process in all these samples. The grain boundary contribution is clearly observed from Cole-Cole plots. The preferential site occupancy of Yttrium ions results in rapid increase of coercivity, hysteresis loops also revealed same effect of substitution. The improved value of coercivity is quite beneficial for the perpendicular recording media which is an emerging technology in the recording media.