Volume 120, Number 2, October 2017
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||17 January 2018|
Enhanced insulating state and diluted Ir4+ spin orders in Ir-vacant Sr2Ir1−xO4 systems
1 School of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications Wenyuan road 9, 210023, Nanjing, PRC
2 College of Science, Center of Advanced Functional Ceramics, Nanjing University of Posts and Telecommunications Wenyuan road 9, 210023, Nanjing, PRC
3 Department of Physics, Nanjing University, National Lab for Solid State Microstructures - 210093, Nanjing, PRC
Received: 27 June 2017
Accepted: 15 December 2017
A series of polycrystalline samples of Sr2Ir1−xO4 has been synthesized by the solid-state reaction method. The evolution of the structure and the physical properties are studied with increasing Ir vacancies. Ir vacancies induce a significant structural change, especially the decrease of the Ir-O-Ir bond angle. This, together with the increasing disorder causes the increasing of resistivity. The sharp decrease of the total moment is attributed to the reduced number of magnetic Ir4+ ions and the weakened exchange interactions resulting from the diluted Ir4+ ions. The enhancement moment at lower temperature is probably due to the long-way exchange interactions of diluted Ir4+ spins via Ir5+ ions. The suppression of the antiferromagnetic transition contrasting to the enhancement of the insulating state may suggest that magnetic order is not the origin of the gap opening in the Sr2IrO4 system.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 72.80.Ga – Transition-metal compounds / 74.62.Dh – Effects of crystal defects, doping and substitution
© EPLA, 2018
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