Structural and magnetic characterization of the complete delafossite solid solution (CuAlO 2) 1x(CuCrO 2) x

Barton, PT, Seshadri, R, Knöller, A and Rosseinsky, MJ ORCID: 0000-0002-1910-2483 (2012) Structural and magnetic characterization of the complete delafossite solid solution (CuAlO 2) 1x(CuCrO 2) x Journal of Physics Condensed Matter, 24 (1). 016002-. ISSN 0953-8984, 1361-648X

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Abstract

We have prepared the complete delafossite solid solution series between diamagnetic CuAlO <inf>2</inf>and the t <inf>2g</inf> ³frustrated antiferromagnet CuCrO <inf>2</inf>. The evolution with composition x in CuAl <inf>1x</inf>Cr <inf>x</inf>O <inf>2</inf>of the crystal structure and magnetic properties has been studied and is reported here. The room-temperature unit cell parameters follow the Végard law and increase with x as expected. The <inf>eff</inf> is equal to the Cr ³⁺ spin-only S=3/2 value throughout the entire solid solution. <inf>CW</inf> is negative, indicating that the dominant interactions are antiferromagnetic, and its magnitude increases with Cr substitution. For dilute Cr compositions, the nearest-neighbor exchange coupling constant J <inf>BB</inf> was estimated by mean-field theory to be 3.0meV. Despite the sizable <inf>CW</inf>, long-range antiferromagnetic order does not develop until x is almost 1, and is preceded by glassy behavior. The data presented here, and those on dilute Al substitution from Okuda etal, suggest that the reduction in magnetic frustration due to the presence of non-magnetic Al does not have as dominant an effect on magnetism as chemical disorder and dilution of the magnetic exchange. For all samples, the 5K isothermal magnetization does not saturate in fields up to 5T and minimal hysteresis is observed. The presence of antiferromagnetic interactions is clearly evident in the sub-Brillouin behavior with a reduced magnetization per Cr atom. An inspection of the scaled Curie plot reveals that significant short-range antiferromagnetic interactions occur in CuCrO <inf>2</inf>above its Néel temperature, consistent with its magnetic frustration. Uncompensated short-range behavior is present in the Al-substituted samples and is likely a result of chemical disorder. © 2012 IOP Publishing Ltd.

Item Type:	Article
Uncontrolled Keywords:	cond-mat.mtrl-sci, cond-mat.mtrl-sci
Depositing User:	Symplectic Admin
Date Deposited:	28 Jul 2016 14:40
Last Modified:	21 Apr 2026 23:06
DOI:	10.1088/0953-8984/24/1/016002
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3002581
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