Abstract
The complex surface impedance of a number of GdBa2Cu3O7−δ single crystals has been measured at 10, 15 and 21 GHz using a cavity perturbation technique. At low temperature a marked increase in the London penetration depth and surface resistance is observed associated with the paramagnetic and antiferromagnetic alignment of the Gd spins. The penetration depth has a sharp change in slope at the Néel temperature, TN ∼ 2.2K, and the real part of the conductivity peaks at a frequency dependent temperature slightly above TN. The observed temperature and frequency dependence can be described by a model which assumes a negligibly small interaction between the Gd spins and the electrons in the superconducting state, with a frequency dependent magnetic susceptibility and a Gd spin relaxation time τs being a strong function of temperature. Above TN, τs has a component varying as 1/(T − TN), while below TN it increases ∼ T−5.
Original language | English |
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Pages (from-to) | 2689-2690 |
Number of pages | 2 |
Journal | Physica C Superconductivity |
Volume | 341-348 |
Issue number | Part 4 |
DOIs | |
Publication status | Published - 1 Nov 2000 |
Event | International Conference on Materials and Mechanisms of Superconductivity High Temperature Superconductors, 6th - , United Kingdom Duration: 1 Jan 2000 → … |