Structure and magnetism of La x Sr 2− x Co 0.5 Ir 0.5 O 4− y H y (0 < x < 1) iridium-containing oxyhydride phases †

Journal article

Ruddlesden-Popper oxide phases in the LaxSr2−xCo0.5Ir0.5O4 (0 < x < 1) solid solution can be converted to the corresponding LaxSr2−xCo0.5Ir0.5O4−yHy oxyhydride phases, by topochemical reaction with LiH, in which the hydride ions are substituted exclusively onto the equatorial anion sites of the host framework. Analysis reveals that oxyhydride phases in the range 0.5 < x < 1 adopt LaxSr2−xCo0.5Ir0.5O2+xH2−x compositions which maintain a constant Co1+, Ir3+ oxidation-state combination (confirmed by Co K-edge XANES data), with the presence of low-spin d6 Ir3+ being consistent with the covalent stabilization of the metastable oxyhydride phases via strong Ir–H σ-bonds. Phases at the lanthanum-poor end of the solid solution (x < 0.5) adopt LaxSr2−xCo0.5Ir0.5O4−yHy compositions with lower hydride concentrations (y < 1.5). Magnetisation and μSR data indicate that all the LaxSr2−xCo0.5Ir0.5O4−yHy oxyhydride phases exhibit strong magnetic frustration, attributed to the large-scale cation and anion disorder, and resulting in glassy magnetic behaviour at low temperature.

Authors: Murrell, JI; Wernert, R; Wu, HCH; Huddart, BM; Blundell, SJ

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Royal Society of Chemistry
• Journal: Dalton Transactions
• Publication date: 2025-07-23
• Acceptance date: 2025-07-22
• DOI: 10.1039/d5dt00979k
• EISSN: 1477-9234
• ISSN: 1477-9226
• Language: English