RF responses and possible applications of intrinsic Josephson junctions in different vortex states

We report various RF induced effects on Josephson vortex flow of Bi2Sr2CaCu2O8+y intrinsic Josephson junctions in vortex states being different with existence of pancake vortices. For pancake free state, RF induced zero-crossing steps, which had been found in ordinary Josephson flux flow oscillators, were first observed at voltage V = NΦ0f for N-stacked intrinsic Josephson junctions. In contrast the RF irradiations to the junctions in mixed state with pancakes those step responses changed features similar to Shapiro steps at Vn = nNΦ0f with order n. The former evidently demonstrates that electromagnetic waves propagate in the intrinsic Josephson junctions interacting with moving vortices. The later indicates that Josephson vortices move at the same speed coherently.