Fundamental and third harmonics AC susceptibility with applied DC field in YBa2Cu3O7
Abstract
Measurements of the temperature dependence of the fundamental and third harmonic response of the AC susceptibility with applied DC field on bulk YBa2Cu3O7 at hAC = 0.678mT and f1 = 800 Hz were studied. The measurements were done such that the field is too low to allow penetration vortices. Characterization measurements show the formation of YBCO with Tc=84.5oC. It was found out by examining the fundamental harmonic that the real susceptibility is independent of the applied DC field which shows that the losses are due to the eddy currents in the system. The 3rd harmonics show that there is a decrease in prominence in the features of the susceptibility as the amplitude of the DC field is increased. This is due to the diffusion of the magnetic field which decreases the non linearity of magnetic response causing the absence of higher harmonics.