Effects of Ca substitution and the pseudogap on the magnetic properties of Y1-xCaxBa2Cu3O7-delta

TL;DR

This study investigates how calcium substitution and the pseudogap influence the magnetic susceptibility of Y1-xCaxBa2Cu3O7-delta, revealing non-linear effects of Ca and a critical hole content for pseudogap emergence.

Contribution

It demonstrates the impact of Ca substitution on magnetic susceptibility and identifies a specific hole content threshold for pseudogap formation in the material.

Findings

Ca induces a Curie-like magnetic contribution increasing with x

Pseudogap appears abruptly below a hole content of p ≈ 0.19

Statistical Ca clusters influence magnetic properties

Abstract

The effects of planar hole content, p, on the static magnetic susceptibility, chi(T), of Y1-xCaxBa2Cu3O7-delta polycrystalline samples were investigated over a wide range of Ca (x) and oxygen contents. Non-magnetic Ca2+, in the 3p6 state, induces a Curie-like contribution to chi(T) that increases systematically and non-linearly with x but is almost independent of p. We argue that this arises from statistical clusters containing two or more nearest neighbor Ca atoms. We have again found that the pseudogap in the quasi-particle spectral weight appears abruptly below a planar hole content p = 0.190 +/- 0.005.