Study of the electric and magnetic properties in doped pyrochlore iridate Bi_2-xCu_xIr₂O₇

ABSTRACT

In this study, we examined the magnetic and electric properties of the Cu-doped Bi_2-xCu_xIr₂O₇ (x = 0,0.2,0.4,0.6). The X-ray diffraction confirmed that the Bi_2-xCu_xIr₂O₇ had a cubic structure. The electric transport properties indicate that the samples were in a metallic state when x < 0.4, and the metal-insulator transition occurred in the sample at x = 0.6. The behaviour of the resistivity in the composite material was produced by the electron-electron scattering process. The grain boundary effect played a dominant role in the conduction process. It was also found that the antiferromagnetic interactions enhanced with increasing Cu doping at first, but they weakened with further increases in Cu doping. These findings are explained based on the competition among the ferromagnetic Cu–Cu, antiferromagnetic Ir–Ir and antiferromagnetic Ir–Cu interactions.

KEYWORDS:

• Metal-insulator transition
• magnetic interaction
• grain boundary effect

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant number 11604071), Natural Science Foundation of the Education Department of Anhui Province (Grant Nos. KJ2017A548, 2016jyxm0864 gxgnfx2018072 and 2016jyxm0865) and Natural Science Foundation of Anhui Sanlian College (Grant nos. PTZD2018001, 18zlgc019 and PTZD2019030).