Investigation of the quaternary Fe2-xCoxMnSi alloys by structural, magnetic, resistivity and spin polarization measurements

TL;DR

This study explores how Co substitution affects the structural, magnetic, and electronic properties of Fe2-xCoxMnSi alloys, revealing increased Curie temperature and magnetization, the disappearance of AFM phases at higher Co levels, and signs of half-metallicity and spin gapless behavior.

Contribution

It provides new insights into the magnetic interactions and electronic behavior of Fe2-xCoxMnSi alloys with varying Co content, including evidence of half-metallicity and spin gapless semiconducting features.

Findings

Curie temperature and saturation magnetization increase linearly with Co substitution.

AFM phase disappears for x ≥ 0.2, indicating a change in magnetic interactions.

Resistivity measurements suggest half-metallicity and spin gapless semiconducting behavior at certain compositions.

Abstract

Effects of the Co substitution have been observed on the structural, magnetic and magneto-transport properties of Fe2-xCoxMnSi alloy. Curie temperature (TC) and saturation magnetization (MS) of these alloys increased linearly with the Co substitution. Competitive magnetic interaction between ferromagnetic (FM) and anti-ferromagnetic (AFM) phases exists in Fe2-xCoxMnSi for x less than 0.2, AFM phase is completely disappears for x greater than or equal to 0.2. The value of Rhodes-Wohlfarth ratio pc/ps is greater than one for these alloys which is the characteristics of iterant magnetism present in the system. M\"ossbauer spectroscopic measurements have been done to investigate the atomic disorder and local magnetic moment for some x values. Resistivity measurements also confirm the stability of ferromagnetism with the concentration of Co and also show a sign of half metallicity. Resistivity shows semiconducting behaviour for x = 0.4 which is interesting in view of spin gapless semiconductors.