Temperature dependence of rf and microwave absorption in granular HTSC-determination of Josephson and grain penetration depths

Temperature dependence of power absorption of HTSCs is found to follow the London two fluid model at both radio and microwave frequencies. The two fluid model is shown to account for the Josephson penetration depth at radio frequencies (MHz) and grain penetration depth at microwave frequencies in sintered HTSCs. The Josephson penetration depth determined is of the order of 100 μm. Also, it is discussed that reduced superelectron screening due to short mean free path in HTSC cannot account for the large penetration depth determined from the radio frequency absorption.