Material design toward a thermodynamically stable Co–Cr–Fe–Al Heusler-type phase

作者：A. Omar, F. Börrnert, M. Richter, J. Trinckauf, F. Heinsch, C. G. F. Blum, V. Romaka, S. Rodan, F. Steckel, M. Haft, S. Hampel, S. Beckert, A. Thomas, C. Hess, A. Wolter, W. Löser, B. Büchner, S. Wurmehl · 发表于：APL Materials · 年份：2025 · DOI：10.1063/5.0268257 · 被引用次数：1

The development of new materials using band structure calculations has become increasingly popular due to their resource-efficient nature. However, experimental observations often yield unexpected results, primarily as a consequence of peculiarities in thermodynamic phase formation. As an exemplary case study, we consider the Heusler-like phase Co2Cr0.6Fe0.4Al, which was initially proposed to be a half-metallic ferromagnet; but this composition undergoes phase decomposition due to solid-state immiscibility. Consequently, significant discrepancies have been found between predicted properties and measured values, both in bulk samples and thin films. In the present work, a novel Al-rich composition, Co2Cr0.4Fe0.4Al1.2, is designed based on prior studies of phase constitution and phase transformations in Co–Cr–Fe–Al and related systems. An in-depth characterization of samples synthesized using the floating zone technique confirms their single-phase nature. We report an unprecedented agreement between properties evaluated by a subsequent band structure calculation using the modified composition as an input parameter and the resulting experimental properties, where, for instance, x-ray magnetic circular dichroism measurements demonstrate significantly enhanced spin and orbital moments without the need for any scaling factor, unlike in reports on Co2Cr0.6Fe0.4Al. Thus, Co2Cr0.4Fe0.4Al1.2 is a promising thermodynamically stable Heusler-type compound. We, therefore, expect Co2Cr0.4Fe0...