Disorder Mediated Fully Compensated Ferrimagnetic Spin‐Gapless Semiconducting Behavior in Cr 3 Al Heusler Alloy

ABSTRACT Spin‐gapless semiconductors (SGSs) that host fully compensated ferrimagnetism (FCF) are highly sought for energy‐efficient and stray‐field‐free spintronics, yet their realization in chemically disordered systems has remained elusive. Here, we demonstrate that the binary Heusler alloy –despite adopting a fully A2‐disordered structure–exhibits a rare coexistence of SGS transport and an FCF ground state. Single‐crystalline and polycrystalline samples were synthesized, and structural analyzes using single‐crystal XRD, synchrotron powder XRD, and neutron diffraction reveal complete Cr/Al site mixing. Magnetization, X‐ray magnetic circular dichroism (XMCD), and temperature‐dependent neutron diffraction establish a compensated ferrimagnetic state with a vanishing ordered moment of 0.1(1) /f.u and a high Curie temperature of 773 2 K. Electrical and thermal transport measurements uncover SGS characteristics, including weak temperature‐dependent conductivity, low Seebeck coefficients, and electron‐hole compensated transport. Hall measurements show unusual temperature‐dependent carrier concentrations consistent with disorder‐modified electronic states. First‐principles calculations reproduce the experimentally observed negligibly small magnetization (0.0072 /f.u) and reveal a vanishing spin‐up bandgap–supporting SGS behavior driven by chemical disorder. Our results identify as the first experimentally verified A2‐disordered Heusler alloy exhibiting FCF‐characteristics and SGS transport, positioning it as a disorder‐tolerant platform for next‐generation, high‐temperature spintronic devices.