Antiferromagnetic Resonance in MnO: Co: A Measurement of the Magnetoelastic Properties of the Co 2+ Ion
Antiferromagnetic Resonance in MnO: Co: A Measurement of the Magnetoelastic Properties of the Co 2+ Ion
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MnO: Co 中的反铁磁共振：Co 2 离子磁弹性的测量
DOI：
10.1103/physrevb.3.877
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发表时间：
1971
期刊：
影响因子：
--
通讯作者：
A. Hughes
中科院分区：
文献类型：
--
作者：
A. Hughes
在0.5-6.0摩尔%范围内，MnO的”面外”反铁磁共振频率ω_1是Co杂质浓度的函数。使用远红外技术，观察到ω 1从纯MnO的27.7 cm− 1偏移到6.0%Co掺杂的38.0 cm− 1。谱线展宽排除了跟随共振到更高杂质浓度的可能性。ω 1作为温度的函数的测量证实了共振吸收线的磁性，并且与现有的数据一致，这些数据表明混合系统的Néel温度是杂质浓度的线性函数。垂直磁化率，另一方面，似乎变化很小，因为Co被添加到MnO。发现频率ω 1的平方与Co浓度成正比，这表明Co 2+单离子各向异性是造成这种位移的主要原因，从结果中推断出各向异性贡献为32.8 cm− 1/ion。由Kanamori开发的CoO的磁致伸缩的理论进行修改，以处理目前的情况下，它表明，所观察到的各向异性可以很容易地理解在这些条款。CoO的性质的相关性，这一结果进行了讨论，特别是，磁各向异性的问题和动态的Jahn-Teller效应的顺磁状态的可能性。在两个附录中给出了与实验结果解释有关的掺杂反铁磁材料的反铁磁共振和各向异性的一些特征。
The" out-of-plane" antiferromagnetic resonance frequency ω 1 of MnO has been followed as a function of Co-impurity concentration in the range 0.5-6.0 mole%. Using far-infrared techniques, ω 1 is observed to shift from 27.7 cm− 1 in pure MnO to 38.0 cm− 1 for 6.0% Co doping. Line broadening precluded the possibility of following the resonance to higher impurity concentrations. Measurements of ω 1 as a function of temperature confirm the magnetic nature of the resonance absorption lines, and are consistent with existing data which show that the Néel temperature of the mixed system is a linear function of impurity concentration. The perpendicular susceptibility, on the other hand, appears to change very little as Co is added to MnO. The square of the frequency ω 1 is found to be proportional to the Co concentration, suggesting that Co 2+ single-ion anisotropy is primarily responsible for the shift, and an anisotropy contribution of 32.8 cm− 1/ion is deduced from the results. The theory of the magnetostriction of CoO developed by Kanamori is modified to deal with the present case, and it is shown that the observed anisotropy can be readily understood in these terms. The relevance of this result to the properties of CoO is discussed, in particular, the problem of magnetic anisotropy and the possibility of a dynamic Jahn-Teller effect in the paramagnetic state. Some features of antiferromagnetic resonance (AFMR) and anisotropy in doped antiferromagnets relevant to the interpretation of the experimental results are developed in two appendixes.