Near-Room-Temperature Ferromagnetic 1T Nb1−xCrxTe2 from Doping-Induced Phase Transition of 1T′ NbTe2

• • Cr doping at x = 1/3 stabilizes the 1T phase of NbTe2, enabling a ferromagnetic ordering with TC = 254 K, which exceeds the TC of most Cr-based vdW ferromagnets (e.g., CrI3 TC = 61 K, CrGeTe3 TC = 61 K). This near-room-temperature operation is critical for practical spintronic devices that require thermal stability. • • The 1T Nb2/3Cr1/3Te2 single crystal exhibits a positive magnetoresistance of 32.1% at 2 K under 9 T, a metric that indicates potential for magnetic field sensing and non-volatile memory applications where large MR ratios are essential. • • The Kondo effect observed in the metallic state suggests strong spin scattering, which could be exploited for spin injection and detection, but also implies that device performance may degrade at cryogenic temperatures due to enhanced electron scattering. • • The phase transition from 1T′ to 1T is induced by Cr doping, as confirmed by DFT calculations showing thermodynamic stability of the 1T phase at x = 1/3. This provides a design rule for stabilizing metastable phases in other TMD systems, potentially unlocking topological spintronic properties.