Structural transitions, magnetic properties, and electronic structures of Co(Fe)-doped MnNiSi compounds

TL;DR

This study explores how Co and Fe doping affect the structural, magnetic, and electronic properties of MnNiSi compounds, revealing phase transitions, magnetic behavior changes, and electronic structure insights through experiments and calculations.

Contribution

It provides new understanding of how Co and Fe doping influence phase transitions and magnetic properties in MnNiSi, combining experimental and theoretical approaches.

Findings

Martensitic transition temperature decreases with doping.

Ferromagnetic behavior persists in martensite phases.

Calculated magnetic moments agree with experimental data.

Abstract

The structural transitions, magnetic properties, and electronic structures of Co(Fe)-doped MnNiSi compounds are investigated by x-ray powder diffraction (XRD), differential scanning calorimetry (DSC), magnetic measurements, and first-principles calculations. Results indicate that all samples undergo a martensitic transition from the Ni2In-type parent phase to TiNiSi-type orthorhombic phase at high temperatures. The substitution of Co(Fe) for Mn in Mn1-xCoxNiSi (x = 0.2, 0.3, 0.4) and Mn1-yFeyNiSi (y = 0.26, 0.30, 0.36, 0.46, 0.55) samples decreases the structural transition temperature (Tt) and Curie temperature of martensite (TCM). The martensite phases show a typical ferromagnetic behavior with saturation field (HS) being basically unchanged with increasing Co(Fe) content, while the saturation magnetization (MS) shows a decreasing tendency. The theoretically calculated moments are in good agreement with the experimentally measured results. The orbital hybridizations between different 3d elements are analyzed from the distribution of density of states.