• The negative value of imaginary dielectric constant near Fabry–Perot resonance is found to be correlated with the magnetoelectric coupling. This magnetoelectric couping effect produces a transformation between magnetic energy and electric energy. • The dispersion of imaginary parts of electric modulus shows two relaxation time constant for undoped aluminum iron oxide material but one relaxation time constant for manganese doped aluminum iron oxide material. • This effect of managanese doping in the aluminum iron oxide and the transformation of electric and magnetic energy near the Fabry–Perot resonance marks the sample suitable for magnetoelectric sensing devices for medical related applications, which may be asserted as the novelty of this study. This paper reports on the dielectric properties of undoped and manganese doped aluminum iron oxide. The solid state reaction method was was used to synthesis the samples. The dieletic function was measured over the frequency band 1kHz–10MHz at room temperature. The real part of dielectric function shows the material in ferrimagnetic/ferromagnetic order. The negative value of imaginary part of dielectric function near Fabry–Perot resonance is found to be correlated with the magnetoelectric coupling. This magnetoelectric couping effect produces a transformation between magnetic energy and electric energy. The dispersion of imaginary part of electric modulus shows two relaxation time constant for undoped aluminum iron oxide and one relaxation time constant for manganese doped aluminum iron oxide. This effect of managanese doping and transformation of electric and magnetic energy near the Fabry–Perot resonance in aluminum iron oxide may be proclaimed as the novelty of this study. The above figures show the variation of the real part and imaginary part of electric modulus to understand the dielectric behavior of the material by screening out the electrode polarization effect on them.