Interpretation of the Magnetic Properties of LaCoO3
Interpretation of the Magnetic Properties of LaCoO3
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LaCoO3 磁性的解释
DOI：
10.1063/1.1714092
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发表时间：
1965
影响因子：
3.2
通讯作者：
R. Santoro
中科院分区：
文献类型：
--
作者：
C. Naiman;R. Gilmore;B. Dibartolo;A. Linz;R. Santoro
在4.2°至300°K的温度范围内对单晶LaCoO3进行了磁化率测量。我们发现，在300°K时，有效磁矩平方与hekes等人的结论一致，但随着温度的降低，有效磁矩平方下降得更快。在4.2°，77°和300°K的顺磁共振测量排除了少量顺磁性钴的存在，只留下反磁性或高浓度顺磁性Co+3的可能性。（由于化学原因，其他钴价的高浓度被排除在外。）使用Goodenough发现的一个成功的模型，我们假设Co+3在交点附近，1A1态最低。一个包括自旋轨道效应的计算，但假设300°到4.2°K范围内的立方对称，给出了1A1和5T2态重心之间的能量差的线性变化，与立方变化的预期相反。这种效应可以通过包含一个下对称来解释。
Susceptibility measurements have been carried out on single‐crystal LaCoO3 in the temperature range of 4.2° to 300°K. We find an effective magnetic moment squared that agrees with Heikes et al. at 300°K, but which falls more rapidly with decreasing temperature. Paramagnetic resonance measurements at 4.2°, 77°, and 300°K have ruled out the presence of modest quantities of paramagnetic cobalt, leaving only the possibilities of diamagnetic or highly concentrated paramagnetic Co+3. (Large concentrations of other cobalt valencies are ruled out for chemical reasons.) Using a model found successful by Goodenough, we assume that Co+3 is near the crossover point, with the 1A1 state lowest. A calculation including spin‐orbit effects, but assuming cubic symmetry for the 300° to 4.2°K range, gives essentially a linear variation for the energy difference between the 1A1 and the center of gravity of the 5T2 states, opposite to that expected for a cubic variation. This effect can be explained by including a lower symmet...