Charge-Inhomogeneity doping relations in YBCO detected by Angle Dependent Nuclear Quadrupole Resonance

TL;DR

This study uses a novel NQR method to explore charge inhomogeneity in YBCO, revealing it occurs mainly with oxygen deficiency, thus constraining possible inhomogeneity models.

Contribution

Introduces a new experimental approach to measure NQR asymmetry parameter eta across wide lines, linking charge inhomogeneity to oxygen deficiency in YBCO.

Findings

Charge inhomogeneity is present only with oxygen deficiency.

New NQR method effectively measures eta across wide lines.

Charge inhomogeneity is limited in bulk YBCO by oxygen content.

Abstract

The origin of charge inhomogeneity in YBa_{2}Cu_{3}O_{y} is investigated using a new experimental method designed to determine the nuclear quadrupole resonance (NQR) asymmetry parameter eta for very wide NQR lines at different positions on the line. The method is based on the measurement of the echo intensity as a function of the angle between the radio frequency field H1 and the principal axis of the electric field gradient. Static charge inhomogeneity deduced from eta>0 are found in this compound, but only in conjunction with oxygen deficiency. This limits considerably the possible forms of charge inhomogeneity in bulk YBa_{2}Cu_{3}O_{y}.