title: Critical behavior of thermal relaxation near a breakdown point.
abstract: At a composition far above the percolation threshold, the resistance of a composite sample increases with time due to Joule heating as a constant current of a sufficiently large value is passed through the sample. If the current is less than a certain breakdown current (I(b)) the resistance eventually reaches a steady value with a characteristic relaxation time tau(h). The latter diverges with current I as tau(h) approximately (1-I(2)/I(2)(b))(-z). The value of the exponent z displays large fluctuations leading to unusual scaling of the relaxation time. It is shown that the results lead to important conclusions about the nature of breakdown phenomena.
authors.affiliation: Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700 064, India.
authors.forename: C D
authors.initials: CD
authors.lastname: Mukherjee
authors.forename: K K
authors.initials: KK
authors.lastname: Bardhan