Evolution of Ferromagnetism and Electrical Resistivity in Sb-Doped Cr4PtGa17

TL;DR

This study investigates how Sb doping affects the magnetic and electrical properties of Cr4PtGa17, revealing suppression of ferromagnetism and a transition from metallic to semiconducting behavior, with insights into the underlying electronic structure.

Contribution

It provides new insights into the doping-induced evolution of magnetism and resistivity in Cr4PtGa17, highlighting the role of itinerant electrons and electronic structure changes.

Findings

Ferromagnetism is gradually suppressed with Sb doping.

Electrical resistivity shows a metal-semiconductor transition.

Fermi energy increases with Sb content, affecting electronic properties.

Abstract

We describe the doping effects on a metallic breathing pyrochlore compound, Cr4PtGa17. Upon doping with Sb, i.e., Cr4Pt(Ga1-xSbx)17, it was found that a selective doping on one of the seven Ga sites occurs. With increasing dopant level, the ferromagnetism in the parent compound is gradually suppressed, along with a decrease in fitted Curie-Weiss temperature (from 61 (1) K to -1.8 (1) K) and effective moment (from ~2.26 muB/f.u. to ~0.68 muB/f.u.). Low-temperature heat capacity measurements confirm the absence of magnetic ordering above 0.4 K for the three most doped samples. Meanwhile, electrical resistivity measurements display a metal-semiconductor transition with increasing Sb contents, which is attributed to an increase of Fermi energy based on the calculations of electronic band structure and density of states. Moreover, we have speculated that the ferromagnetism in Cr4PtGa17 is governed by itinerant electrons according to our observations. This study of Sb-doping effect on Cr4PtGa17 provides deeper understanding of magnetism of this system and possibilities for future modifications.