1/8 anomaly in the excess-oxygen-doped La_1.8_Nd_0.2_Cu_1-y_Zn_y_O_4+\delta_

TL;DR

This study investigates the 1/8 anomaly in excess-oxygen-doped La_1.8_Nd_0.2_Cu_1-y_Zn_y_O_4+\delta_, revealing suppressed superconductivity, magnetic correlations, and stripe order, especially with Zn substitution, using muon-spin-relaxation measurements.

Contribution

It demonstrates the occurrence of the 1/8 anomaly and magnetic ordering in excess-oxygen-doped La_1.8_Nd_0.2_Cu_1-y_Zn_y_O_4+\delta_ with detailed magnetic characterization.

Findings

Suppression of superconductivity at p=1/8

Magnetic correlations develop below 50 K

Long-range magnetic order observed with Zn substitution

Abstract

We have found the 1/8 anomaly, namely, the anomalous suppression of superconductivity at p (the hole concentration per Cu) = 1/8 in the excess-oxygen-doped La_1.8_Nd_0.2_Cu_1-y_Zn_y_O_4+\delta_, where the excess oxygen is doped by the electrochemical technique and the phase separation of the excess oxygen is suppressed. The 1/8 anomaly has become marked by the 1 % substitution of Zn for Cu. The muon-spin-relaxation measurements have revealed that the magnetic correlation develops at low temperatures below about 50 K in both Zn-free and 1 % Zn-substituted samples with p = 1/8. Clear precession of muon spins suggesting the formation of a long-range magnetic order has been observed below 1 K in the 1 % Zn-substituted sample with p = 1/8. These results are consistent with the stripe-pinning model.