Spin Gaps and Spin Dynamics in La_{2-x}Sr_xCuO_4 and YBa_2Cu_3O7_\delta

TL;DR

This paper investigates the spin gaps and dynamics in cuprate superconductors, proposing mechanisms for magnetic susceptibility behavior related to antiferromagnetic ordering and fluctuations in different compounds.

Contribution

It introduces specific explanations for the magnetic susceptibility decrease in La_{2-x}Sr_xCuO_4 and YBa_2Cu_3O_{6.6} based on antiferromagnetic interactions and pairing.

Findings

Antiferromagnetic ordering is suppressed by low dimensionality in La_{2-x}Sr_xCuO_4.

Interplay of fluctuations and pairing explains susceptibility in YBa_2Cu_3O_{6.6}.

Magnetic behavior linked to spin gaps and electron pairing mechanisms.

Abstract

A magnetic susceptibility which decreases with decreasing temperature is observed in all $CuO_2$ based superconductors with less than optimal doping. We propose that in $La_{2-x} Sr_x CuO_4$ this is due to antiferromagnetic ordering which is prevented by the low spatial dimensionality while in $YBa_2 Cu_3 O_{6.6}$ it is due to the interplay between antiferromagnetic fluctuations within a plane and singlet pairing of electrons between nearest neighbor planes.