Abstract
In this paper, the critical current density measured from the real part of ac-susceptibility is in agreement with that calculated from Bean's formula at constant frequency (f = 98 Hz) in the temperature range 30-38K for a pure MgB2 sample. The temperature dependence of the imaginary part of ac-susceptibility (chi ''-T) shows the shifts in absorption peaks towards the lower temperature when the applied field is increased. Scanning electron microscopy images confirmed the synthesis of a good sample and agglomerates with fine grains.