Possible phase separated bulk superconductivity in Ru0.9Sr2YCu2.1O7.9

TL;DR

This study investigates Ru0.9Sr2YCu2.1O7.9, revealing weak ferromagnetism at 150 K and superconductivity at 30 K, with evidence suggesting phase separation rather than microscopic coexistence of magnetism and superconductivity.

Contribution

It provides experimental evidence that Ru0.9Sr2YCu2.1O7.9 exhibits phase-separated magnetic and superconducting regions rather than microscopic coexistence.

Findings

Superconducting transition at 30 K observed.

Weak ferromagnetic transition at 150 K detected.

Magnetic and superconducting behaviors explained by phase separation.

Abstract

The Ru0.9Sr2YCu2.1O7.9 sample being synthesized by high-pressure high-temperature solid-state reaction underwent (weak) ferromagnetic transition at 150 K followed by superconducting transition at 30 K. It showed clear Meissner signal in the field-cooled process up to external magnetic field of a few hundred Oe (~300 Oe). The magnetic susceptibility data and magnetic hysteresis data could be explained assuming that the sample was a macroscopic mixture of a superconductor and a (weak) ferromagnet. Any anomalous behaviour implying the coexistence of superconductivity and magnetism on a microscopic scale was not observed.