In this study, we have systematically calculated the dynamic susceptibility spectra of LSMO (La_0.7Sr_0.3MnO₃) ferromagnetic nanopillars by means of a micromagnetic simulation. Simulation has been carried out for LSMO nanopillars consisted of disk and square shapes with respect to the height variation. The diameter of disk pillar and the length of square pillar were fixed to be 50 nm and the height of pillar were varied from 100 to 500 nm with increment of 50 nm. The exponential type magnetic pulses have been applied in the long axis and perpendicular to the initial spin configuration of the pillars. The dynamic susceptibility spectra of the pillar were determined by fast Fourier transform (FFT) based on the magnetization response. We have obtained the resonance frequency of the pillars from the imaginary part of the dynamic susceptibility spectra. Interestingly, the resonance frequency peak of the nanopillars increased as the height increased and followed the Kittel’s resonance formula. It was found that the demagnetization energy from dipolar interaction mainly contributed to
the frequency resonance of the nanopillars.