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We report a combined theoretical and experimental study of the quaternary Heusler alloy CoFeVAl hosting various interesting electronic/magnetic features including an extended Griffiths phase--like behavior. The room temperature x-ray diffraction pattern confirms a cubic structure (space group No. 216) with a B2 disorder between V and Al atoms. The dc magnetization measurements indicate a ferromagnetic-like behavior with a magnetic transition temperature (T₂) 50 K. Above T₂ an unusual magnetic phase (extended Griffiths like) is observed which is carefully analyzed from the dc and ac magnetic susceptibility data. Longitudinal resistivity data confirm a metallic-like behavior with a negative nonsaturating magnetoresistance in the magnetically ordered region. The anomalous Hall effect mediated by a non-negligible intrinsic mechanism is found in the total Hall resistivity whereas negative slope in the ordinary Hall resistivity indicates the electron-mediated conduction in CoFeVAl. First-principles calculated results corroborate well with the experimentally observed crystal structure and nearly half-metallic ferromagnetic (FM) behavior. A high spin polarization (86%) is observed in the FM ground state. Inclusion of B2 disorder retains the nearly half-metallic behavior of CoFeVAl. Such combined studies for the discovery of new quantum materials are the backbone of a future path toward the spintronic-based device applications.
Bandyopadhyay et al. (Mon,) studied this question.