Cu(2) nuclear resonance evidence for an original magnetic phase in aged 60K-superconductors RBa2Cu3O6+x (R=Tm,Y)

TL;DR

This study uses copper nuclear magnetic resonance to reveal that aged RBa2Cu3O6+x superconductors retain magnetic order at higher oxygen levels and temperatures than previously thought, challenging existing beliefs about their magnetic properties.

Contribution

It provides new evidence of magnetic order in aged superconductors at oxygen contents up to 0.7, extending understanding of their magnetic phases.

Findings

Magnetic order persists at oxygen content x up to 0.7.

Magnetic order observed at temperatures as high as 77K.

Contradicts the belief that magnetic order is suppressed above x>0.4.

Abstract

It is widely believed that the long-range antiferromagnetic order in the RBa2Cu3O6+x compounds (R=Y and rare earths except of Ce, Pr, Tb) is totally suppressed for the oxygen index x>0.4 (AFM insulator-metal transition). We present the results of the copper NQR/NMR studies of aged RBa2Cu3O6+x (R=Tm,Y) samples showing that a magnetic order can still be present at oxygen contents x up to at least 0.7 and at temperatures as high as 77K.