Structure and Anisotropic Properties of BaFe2-xNixAs2 (x = 0, 1, 2) Single Crystals

TL;DR

This study investigates the crystal structure, anisotropic electrical and magnetic properties, and phase transitions of BaFe2-xNixAs2 single crystals, revealing structural, magnetic, and superconducting behaviors across different compositions.

Contribution

It provides a comparative analysis of structural and physical properties of BaFe2-xNixAs2 compounds, highlighting phase transitions and superconductivity in these materials.

Findings

BaFe2As2 exhibits antiferromagnetic transition at 132 K.

BaNi2As2 undergoes a structural phase transition at 131 K and becomes superconducting below 0.69 K.

BaFeNiAs2 shows no superconductivity down to 0.4 K and behaves as a paramagnetic metal.

Abstract

The crystal structure, anisotropic electrical resistivity and magnetic susceptibility, as well as specific heat results from single crystals of BaFe2As2, BaNi2As2, and BaFeNiAs2 are surveyed. BaFe2As2 properties demonstrate the equivalence of C(T), Fisher's d(XT)/dT, and dp/dT results in determining the antiferromagnetic transition at TN = 132(1) K. BaNi2As2 shows a structural phase transition from a high-temperature tetragonal phase to a low-temperature triclinic (P-1) phase at T0 = 131 K.The superconducting critical temperature for BaNi2As2 is well below T0 and at Tc = 0.69 K. BaFeNiAs2 does not show any sign of superconductivity to 0.4 K and exhibits properties similar to BaCo2As2, a renormalized paramagnetic metal.