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Structures and magnetic ordering in layered Cr oxide arsenides Sr2CrO2Cr2OAs2 and Sr2CrO3CrAs

DOI: 10.1021/acs.inorgchem.2c01773 DOI Help

Authors: Bradley C. Sheath (University of Oxford) , Xiaoyu Xu (University of Oxford) , Pascal Manuel (ISIS Facility) , Joke Hadermann (University of Antwerp) , Maria Batuk (University of Antwerp) , John O’sullivan (University of Oxford) , Ruy S. Bonilla (University of Oxford) , Simon J. Clarke (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Inorganic Chemistry

State: Published (Approved)
Published: July 2022
Diamond Proposal Number(s): 18786 , 25166

Open Access Open Access

Abstract: Two novel chromium oxide arsenide materials have been synthesized, Sr2CrO2Cr2OAs2 (i.e., Sr2Cr3As2O3) and Sr2CrO3CrAs (i.e., Sr2Cr2AsO3), both of which contain chromium ions in two distinct layers. Sr2CrO2Cr2OAs2 was targeted following electron microscopy measurements on a related phase. It crystallizes in the space group P4/mmm and accommodates distorted CrO4As2 octahedra containing Cr2+ and distorted CrO2As4 octahedra containing Cr3+. In contrast, Sr2CrO3CrAs incorporates Cr3+ in CrO5 square-pyramidal coordination in [Sr2CrO3]+ layers and Cr2+ ions in CrAs4 tetrahedra in [CrAs]− layers and crystallizes in the space group P4/nmm. Powder neutron diffraction data reveal antiferromagnetic ordering in both compounds. In Sr2CrO3CrAs the Cr2+ moments in the [CrAs]− layers exhibit long-range ordering, while the Cr3+ moments in the [Sr2CrO3]+ layers only exhibit short-range ordering. However, in Sr2CrO2Cr2OAs2, both the Cr2+ moments in the CrO4As2 environments and the Cr3+ moments in the CrO2As4 polyhedra are long-range-ordered below 530(10) K. Above this temperature, only the Cr3+ moments are ordered with a Néel temperature slightly in excess of 600 K. A subtle structural change is evident in Sr2CrO2Cr2OAs2 below the magnetic ordering transitions.

Journal Keywords: Chemical structure; Ions; Layers; Order; Transition metals

Subject Areas: Chemistry, Materials

Instruments: I11-High Resolution Powder Diffraction

Other Facilities: WISH at ISIS

Added On: 01/08/2022 08:58


Discipline Tags:

Physical Chemistry Chemistry Materials Science Inorganic Chemistry

Technical Tags:

Diffraction X-ray Powder Diffraction