Gd3+ ESR determination of the local spin susceptibility in Gd:YBa2Cu3Oy high-temperature superconductors

Abstract

Gd3+ ESR at high fields in Gd-doped high-Tc superconductors is shown to be a precise probe of the conduction electron static spin susceptibility, χ. The Gd3+ ESR Knight shift at 245 GHz and the spin relaxation broadening at 245 and 9.2 GHz in Gd0.01Y0.99Ba2Cu3Oy (with various values of y between 6.05 and 7.0) are in agreement with published Y89 NMR data above 70 K and provide additional measurements at the rare earth site at much lower temperatures. In the superconducting compounds χ(T) differs strongly from the Yoshida function and at low T it follows a T or T2 dependence. An anomalous ESR line shape is found at low T in the superconducting state; we provisionally attribute this to a small (10−2–10−3 μB) static magnetic moment on planar Cu sites. © 1996 The American Physical Society.

Source-reported materials — not catalogue approval

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