Structural and magnetic characterization of the complete delafossite solid solution (CuAlO2)1-x(CuCrO2)x.
Structural and magnetic characterization of the complete delafossite solid solution (CuAlO2)1-x(CuCrO2)x.
复制标题
完整铜铁矿固溶体 (CuAlO2)1-x(CuCrO2)x 的结构和磁性表征。
DOI：
10.1088/0953-8984/24/1/016002
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Barton PT
中科院分区：
文献类型：
--
作者：
Barton PT
We have prepared the complete delafossite solid solution series between diamagnetic CuAlO 2 and the t 2g 3 frustrated antiferromagnet CuCrO 2. The evolution with composition x in CuAl 1− x Cr x O 2 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 μ eff is equal to the Cr 3+ spin-only S= 3/2 value throughout the entire solid solution. Θ CW 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 BB was estimated by mean-field theory to be 3.0 meV. Despite the sizable Θ CW, 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 et al, 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 5 K isothermal magnetization does not saturate in fields up to 5 T 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 2 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.
