Half‐Metallicity in Quaternary Heusler Alloys with 3d and 4d Elements: Observations and Insights from DFT Calculations. Issue 8 (12th April 2019)

• Record Type: Journal Article
• Authors: Ghosh, Srikrishna; Ghosh, Subhradip
• Is Part Of: Physica status solidi. Volume 256:Issue 8(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-04-12
• Subjects: computational physics -- density functional theory -- electronic band structure -- half‐metals -- Heusler alloys -- magnetism; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201900039
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : In this work, important insights into the evolution of half‐metallicity in quaternary Heusler alloys are provided. Employing ab initio electronic structure methods we study 18 quaternary Heusler compounds having the chemical formula CoX′Y′Al, where Y′ = Mn, Fe; and X′ a 4 d element. Along with the search for new materials for spintronics applications, the trends in structural, electronic, magnetic properties, and Curie temperature are investigated. Comparative studies with the compounds in the quaternary series CoX′Y′Si with X′ materials from the 3 d and 4 d transition metal series in the periodic table have been made. We observe that the half‐metallic behavior depends primarily on the crystal structure type based on atomic arrangements and the number of valence electrons. As long as these two are identical, the electronic structures and the magnetic exchange interactions bear close resemblances. Consequently, the materials exhibit identical electronic properties, by and large. The roles of different transition metal atoms in affecting the hybridizations and their correlations with the above observations are analyzed. This work, therefore, provides important perspectives regarding the underlying physics of half‐metallic behavior in quaternary Heusler compounds which goes beyond specifics of a given material. This, thus, paves the way for smart prediction of new half‐metals. This work also figures out an open problem of understanding how different ternary Heuslers with different electronic behavior may lead to half‐metallic behavior in quaternary Heuslers with 4 d transition metal elements. Abstract : The possibilities of finding new half‐metals in quaternary Heusler compounds having both 3 d and 4 d elements along with insight into the role of different elements, structure types, and the number of valence electrons are investigated with density functional theory calculations. The importance of this work is that apart from expanding the database of half‐metals it brings into light certain trends in the electronic structure leading to halfmetallicity which help visualizing a generalized picture of physical effects that give rise to half‐metallic behavior in Heusler compounds.