  The resistive and reactive parts of the magneto-impedance of sintered
ferromagnetic samples of La0.7Sr0.3-xAgxMnO3 (x = 0.05, 0.25) have been
measured at room temperature (<Tc) over frequency interval 1KHz to 15MHz and in
presence of magnetic field up to 4KOe. The field dependence of relative change
in resistance is small in KHz region but increases strongly for higher
frequency of excitation. The maximum value of relative change in resistance at
H =4KOe was found to be around 70% at 15MHz frequency.On the contrary the
corresponding change in reactance has less frequency sensitivity and the
maximum occurs at 1MHz frequency. The magneto-impedance is negative for all
frequencies. The 'normalized magneto-impedance' as defined by
[Z(H)-Z(0)]/[Z(0)-Z(4K)] when plotted against scaled field H/H1/2 is found to
be frequency independent ; H1/2 is the field where 'normalized
magneto-impedance' is reduced to half its maximum. A phenomenological formula
for magneto-impedance Z (H) in ferromagnetic material is proposed based on Pade
approximant. The formula for Z (H) predicts the scaled behavior of 'normalized
magneto-impedance'.
