## Abstract

We have measured the current-voltage {TV) curves in the granular PrBa2Cu3O7_δ compound. We find that they are nonlinear when the bias is high enough. The experimental curves can be well described by I=Σ0 V+Σ1 Vb, where Σ0 is the linear conductance, Σ1 is the high-order conductance, and the degree of the nonlinear term is found to be either b = 2 or 3. We observe that the critical current, IC, at which the nonlinear contribution becomes comparable with the linear contribution, scales with Σ0 as Ic≍ Σ0x, with x=0.56 -0.02 for the two cases b = 2 and 3. We also observe that Σ1 scales with Σ0 as Σ1≍Σ;0y, with y=1.43 -0.05 (for b=2) or 1.92-0.06 (for b=3). These experimental values of x and y are in line with the theoretical prediction based on a nonlinear-random-resistor-network model.

Original language | English |
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Pages (from-to) | 4125-4132 |

Number of pages | 8 |

Journal | Journal of the Physical Society of Japan |

Volume | 61 |

Issue number | 11 |

DOIs | |

State | Published - 15 Nov 1992 |

## Keywords

- critical current
- granular structure
- high-order conductance
- nonlinear I-V characteristics
- percolation
- PrBa2Cu3O7-δ compound
- random resistor networks
- scaling