Nontrivial Recurrent Intergrowth Structure and Unusual Magnetic Behavior of Intermetallic Compound Fe32+delta Ge33As2

作者：Khalaniya Roman A; Mironov Andrei V; Verchenko Valeriy Yu; Jesche Anton; Tsirlin Alexander A; Shevelkov Andrei V^*

来源：Inorganic Chemistry, 2016, 55(24): 12953-12961.

DOI：10.1021/acs.inorgchem.6b02412

A new phase Fe32+delta Ge33As2 (delta <= 0.136) was obtained by two-step synthesis from the elements. Fe32+delta Ge33As2 crystallizes in its own structure type (space group P6/mmm, Z = 1, a = 11.919(3) angstrom, c = 7.558(4) angstrom) that can be described as a recurrent two-dimensional intergrowth of two intermetallic structure types, MgFe6Ge6 and Co2Al5. Their blocks are represented by infinite columns in the structure. No visible structural changes were observed in the temperature range from 10 to 300 K. At 125 K, Fe32+delta Ge33As2 undergoes an antiferromagnetic-like transition, while above 150 K it shows a typical Curie Weiss paramagnetic behavior. Below the transition temperature, a peculiar field-dependent magnetic susceptibility, that shows a significant increase of the susceptibility upon increasing the magnetic field, and a change in transport properties have been observed. Above 140 K, Fe32+delta Ge33As2 reveals a metallic behavior, in agreement with electronic structure calculation, while below this point the resistivity nonmonotonically increases upon cooling. The Seebeck coefficient is positive, indicating that holes are the major charge carriers, and shows a broad maximum around 57 K.

• 出版日期2016-12-19