Enhanced insulating state and diluted Ir4+ spin orders in Ir-vacant Sr2Ir1−xO4 systems. (17th January 2018)

• Record Type: Journal Article
• Authors: Yu, Huiting; Liu, Shengli; Li, Bin; Wang, Haiyun; Cheng, Jie; Wang, Z. H.
• Is Part Of: Europhysics letters. Volume 120:Number 2(2017:Oct.)
• Publication Date: 2018-01-17
• Subjects: 71.27.+a -- 72.80.Ga -- 74.62.Dh; Physics -- Periodicals; Electronic journals; 530.05
• DOI: 10.1209/0295-5075/120/27007
• Languages: English
• ISSNs: 0295-5075

Abstract

Abstract: A series of polycrystalline samples of Sr2 Ir1− x O4 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 Ir 4+ ions and the weakened exchange interactions resulting from the diluted Ir 4+ ions. The enhancement moment at lower temperature is probably due to the long-way exchange interactions of diluted Ir 4+ spins via Ir 5+ 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 Sr2 IrO4 system.