arXiv subjects

Sonali S. Pradhan

Publications and source records attributed to Sonali S. Pradhan.

2 recordsLinked to original sources

arXiv2026

Disorder-driven competing magnetic interactions and glassy magnetic behavior in quaternary Heusler alloy FeRuMnGe

In this combined experimental and theoretical study, we investigate the role of disorder in governing the magnetic ground state of the quaternary Heusler alloy FeRuMnGe. In the FeRuMnZ (Z = Ga, Si) series, chemical substitution modifies atomic ordering and electronic structure, resulting in distinct magnetic ground states. Motivated by this, we extend the series to FeRuMnGe. X-ray diffraction reveals B2-type antisite disorder, where Fe--Ru and Mn--Ge intermix. Theoretical calculations show that such disorder modifies exchange interactions, leading to competing ferromagnetic and antiferromagnetic couplings, and drives the system from half-metallic to metallic. Magnetic measurements reveal competing interactions, giving rise to a cluster-glass state coexisting with long-range magnetic order. The absence of a thermodynamic signature at $T_f$, together with ac susceptibility and relaxation measurements, supports the presence of short-range magnetic interactions and a glassy magnetic state. The compound exhibits an enhanced magnetic response below $\sim 161$ K and a maximum magnetization of $\sim 1.64~μ_B$/f.u. at 5 T. Overall, this work establishes a direct correlation between antisite disorder, competing exchange interactions, and glassy magnetism in quaternary Heusler alloys. Combined experimental results and theoretical calculations reveal that disorder drives the system from an AFM-dominated state in FeRuMnSi to an FM-dominated state in FeRuMnGe, providing deeper insight into the role of the extent of disorder in governing the magnetic properties of QHAs.

cond-mat.str-el↗

arXiv2026

Room temperature intrinsic anomalous Hall effect in disordered half-metallic ferromagnetic quaternary Heusler alloy CoRuFeSi

Quaternary Heusler alloys offer a versatile platform for engineering magnetic and topological transport phenomena through chemical flexibility and tunable disorder. Here, we report a comprehensive experimental and theoretical investigation of the magnetic, magnetotransport, and anomalous Hall properties of the quaternary Heusler alloy CoRuFeSi. The compound crystallizes in the LiMgPdSn-type structure with significant Co--Ru antisite disorder and exhibits soft ferromagnetism with a saturation magnetization of $4.21~μ_{\mathrm{B}}/\mathrm{f.u.}$ at low temperature and a Curie temperature well above room temperature. Hall measurements reveal a robust anomalous Hall effect persisting up to 300~K, with an anomalous Hall conductivity of $\sim 74$~S/cm that is nearly temperature independent. Scaling analysis demonstrates that the anomalous Hall response is dominated by the intrinsic Berry-curvature mechanism. First-principles calculations identify CoRuFeSi as a topologically nontrivial nodal-line semimetal in its ordered phase. Incorporation of experimentally relevant Co--Ru antisite disorder redistributes the Berry curvature and quantitatively reproduces the experimentally observed anomalous Hall conductivity, while preserving half-metallicity. These results establish CoRuFeSi as a disorder-tolerant half-metallic ferromagnet with a sizable intrinsic anomalous Hall effect at room temperature, highlighting its potential for spintronic and Hall-based device applications.

cond-mat.mtrl-sci↗