Influence of Cu Doping on the Electronic Structure and Magnetic Properties of the Mn₂VAl Heusler Compound

Abstract

Detailed investigations on the electronic and magnetic properties of the Heusler compounds Mn2−xCuxVAl with L21 structure have been performed. Polycrystalline samples have been examined by X‐ray diffraction and magnetization measurements have been performed. The degrees of the B2 and L21 atomic ordering obtained from the intensity ratios of the X‐ray patterns have been determined. The Curie temperatures decrease with Cu content, ranging between 771 K (x = 0) and 580 K (x = 0.5). Additionally, electronic band structure calculations using the Korringa–Kohn–Rostoker (KKR) Green's function method have been performed. The substitutional disorder was accounted by the means of the Coherent Potential Approximation (CPA). The site occupation considered in the calculations has been correlated with those obtained by the X‐ray experiments. Our study is giving an insight on the evolution of the half‐metallic fully compensated ferrimagnet (HMFi) character with disorder and Cu doping showing restrictions in obtaining of a HMFi by doping with 3d metals.

Reduction of the substitutional disorder by heat treatments in Mn2-xCoxVAl Heusler alloys

“…The second order parameter S L21 describes the probability of V to occupy the Y position in the X 2 YZ full Heusler alloys: Table 1. Previously we have shown that any changes of these parameters will significantly influence the magnetic and electronic properties of Mn 2-x M x VAl (M = Co or Cu) Heusler systems [6,7]. As can be seen in Table 1, a substantial degree of mixing between the V and Al is present in all our samples.…”

“…The presence of a considerable atomic disorder in the Mn2VAl compound due to the intermixing of the V and Al atoms has been reported [5]. Previous studies have shown that the magnetic properties and the half-metallic character of these Heusler alloys are strongly influenced by the crystallographic disorder [1,3,6,7]. The aim of the present work is to reduce the substitutional disorder by heat treatments in Mn 2−x Co x VAl Heusler alloys.…”

Active Contours Driven by Cellular Neural Networks for Image Segmentation in Biomedical Application

“…It also can be employed in processing uni-dimensional image profiles for the determination of the magnitude and location of profile peaks. As a result, increased accuracy for the determination of structural ordering parameters is obtained (Gavrea et al, 2017). Further on, the procedure of evolving an initial contour based on edge features determined by CNN is explained.…”

Distinct impact of order degree on thermoelectric power factor of p-type full-Heusler Mn2VAl compounds

“…Our previous work revealed that a half-metallic full-Heusler Mn 2 VAl compound is a promising p-type TE material [17]. Compared with other full-Heusler compounds, the Mn 2 VAl compound has an advantage that it can be easily prepared by various methods such as arc-melting [17,[19][20][21], spark-plasmasintering (SPS) [17], induction-melting [22,23], and ultra-high-vacuum magnetron sputtering technique [24][25][26]. A disadvantage of the Mn 2 VAl compound is its low PF=2.7×10 −4 Wm −1 K −2 at 717 K [17], being inferior to an n-type half-metallic full-Heusler Co 2 MnSi compound (2.9×10 −3 Wm −1 K −2 at 550 K [16]).…”