Magnetic and transport properties in Gd$_{1-x}$Sr$_x$CoO$_{3}$ ($x$= 0.10-0.70)

TL;DR

This study systematically explores how varying Sr doping levels in Gd$_{1-x}$Sr$_x$CoO$_{3}$ affects its magnetic and transport properties, revealing complex magnetic states and insulator-metal transitions influenced by ionic size effects.

Contribution

It provides new insights into the doping-dependent magnetic and transport behaviors in Gd-based cobaltates, highlighting the role of ionic size in stabilizing different electronic states.

Findings

Cluster-glass magnetism for x ≤ 0.45

Long-range ferromagnetic order for higher x

Insulator-metal transition around x = 0.35

Abstract

Magnetic and transport properties of polycrystalline Gd$_{1-x}$Sr$_x$CoO$_{3}$ ($x$= 0.10-0.70) are investigated systemically. Cluster-glass magnetism for $x \leq$ 0.45 and long-range ferromagnetic order in higher doping level are observed. Transport measurements indicate insulator-like behaviors for the samples with $x \leq$ 0.30, and an insulator-metal (IM) transition around $x$ = 0.35, and metallic behaviors for higher $x$ samples. In contrast to La$_{1-x}$Sr$_{x}$COO$_{3}$, the striking feature is that the system reenters insulator-like state for $x \geq$ 0.60, and the long-range ferromagnetic order and IM transition take place in samples with higher Sr content. It could be attributed to the enhancement of low-spin state stability for the trivalent Co ions due to the small radius of Gd$^{3+}$ ion.