Effect of Cu-doping on the magnetic and electrical transport properties of three-quarter Heusler alloy ZrCo1.5Sn

Recently, defective three-quarter Heusler compounds MCo1.5Sn (M=Ti, Zr, and Hf) have been reported with interesting crystal structure differing from the traditional half-Heusler and full-Heusler compounds. These defective compounds are metallic ferromagnets, but the detailed correlation between magnetic and electrical transport properties is still unclear. In this study, we dope Cu in ZrCo1.5Sn to dilute the magnetic Co atoms with the purpose of clarifying how the magnetism influences the electrical transport properties in the defective three-quarter Heusler compounds. Significantly lowered ferromagnetic transition temperature and decreased saturated magnetic moment are observed in Cu-doped ZrCo1.5Sn due to the diluted Co atoms. Likewise, in the ferromagnetic phase, the dominant carrier scattering mechanism is changed from spin fluctuation scattering to magnetic impurity scattering. The doped Cu atoms introduce non-bonding states below the valence band maximum, resulting in the appearance of a narrow bandgap around 0.1eV. Correspondingly, the electric transport behavior in the paramagnetic phase shows a semiconducting character with a negative temperature dependence of resistivity. This study provides further understanding to the correlation between magnetic properties and electrical transport properties in defective Heusler-based compounds.

Automated summary

This study investigates how magnetism influences the electrical transport properties in defective three-quarter Heusler compounds by doping Cu in ZrCo1.5Sn. The results show significantly lowered ferromagnetic transition temperature and decreased saturated magnetic moment due to the diluted Co atoms, as well as a change in dominant carrier scattering mechanism from spin fluctuation scattering to magnetic impurity scattering. Doped Cu atoms introduce non-bonding states below the valence band maximum, leading to the appearance of a narrow bandgap and semiconducting behavior in the electric transport properties.