Suppressed rf dissipation in $^{107}Ag^{17+}$ ion irradiated $Bi_2Sr_2CaCu_2O_8$ single crystals by enhanced flux line tilt modulus

Sudershan, YS and Rastogi, Amit and Bhat, SV and Grover, AK and Yamaguchi, Y and Oka, K and Nishihara, Y and Senapati, L and Kanjilal, D (1998) Suppressed rf dissipation in $^{107}Ag^{17+}$ ion irradiated $Bi_2Sr_2CaCu_2O_8$ single crystals by enhanced flux line tilt modulus. In: Applied Physics Letters, 72 (18). pp. 2325-2327.

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Abstract

We have studied the isothermal, magnetic field $(H\parallel c)$ dependent rf power P(H) dissipation $(H_{rf}\parallel a)$ in the superconducting state of $Bi_2Sr_2CaCu_2O_8$ single crystals prior to and after irradiation with 250 MeV $^{107}Ag^{17+}$ ions. In the pristine state, P(H) shows an initial decrease with increase in field, reaches a minimum at $H_M(T)$ and increases monotonically for $H\lessthanH_M(T)$. This behavior arises when the electromagnetic coupling between the pancake vortices in adjacent CuO layers becomes dominant on increasing the field and minimizes the distortions of the flux lines by confining the 2D vortices. In the post irradiated state, such an initial decrease and the minimum in P(H) is not observed but only a much reduced rf dissipation that monotonically increases with field from H50 onwards is seen. We attribute this difference to the strong enhancement of the tilt modulus $C_{44}$ of the flux lines on irradiation when the pancake vortices in adjacent CuO bilayers are pinned along the track forming a well-stacked flux line in the field direction $(\parallel c)$. We have also observed that the rf dissipation disappears at a certain temperature $T_{sf}$ , at which the normal core of the flux line becomes commensurate with the columnar track diameter.

Item Type:	Journal Article
Publication:	Applied Physics Letters
Publisher:	AIP
Additional Information:	Copyright of this article belongs to The American Institute of Physics.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	03 Jan 2007
Last Modified:	19 Sep 2010 04:33
URI:	http://eprints.iisc.ac.in/id/eprint/9197

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