尖晶石到钙铁石榴石的转变：β-CdCr2O4 的机制和性能。

Spinel to CaFe2O4 transformation: mechanism and properties of beta-CdCr2O4.

机构信息

Departamento de Química Inorgánica, Facultad de Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.

出版信息

Inorg Chem. 2010 Mar 15;49(6):2827-33. doi: 10.1021/ic902228h.

PMID:20155927

Abstract

The CdCr(2)O(4) spinel transforms to a 10.6% denser new polymorph of the CaFe(2)O(4)-type structure at 10 GPa and 1100 degrees C. This new polymorph has a honeycomb-like structure because of double rutile-type chains formed by [Cr-O(6)] edge-shared octehedra. This crystal structure is prone to be magnetically frustrated and presents low-dimensional antiferromagnetism at 25 K < T < 150 K, accompanied by more complex interactions as the temperature decreases. These transitions are evidenced by magnetic susceptibility and heat capacity measurements. We also discuss a possible structural mechanism for the transformation.

摘要

在 10 GPa 和 1100°C 的条件下，CdCr(2)O(4)尖晶石转变为一种新的、密度增加 10.6%的 CaFe(2)O(4)型结构多晶型物。由于由 [Cr-O(6)] 共用边八面体形成的双金红石型链，这种新的多晶型物具有蜂窝状结构。由于这种晶体结构容易受到磁各向异性的影响，因此在 25 K < T < 150 K 的温度范围内呈现出低维反铁磁性，并且随着温度的降低会出现更为复杂的相互作用。这些转变可以通过磁化率和热容测量来证明。我们还讨论了这种转变的可能结构机制。