Griffiths phase and spontaneous magnetization in polycrystalline Co50V34Ga16 alloy

Highlights: • Griffiths phase was first discovered in directional solidification of Co₅₀V₃₄Ga₁₆ alloy. • Susceptibility and Spontaneous magnetization confirm the existence of Griffiths phase. • Arrott plots and Bean-Rodbell model to determine the transition type around T_C. • Spin wave excitation was used to reveals ferromagnetic properties of the alloy at low temperatures. -- Abstract: In this work, we synthesized the Co₅₀V₃₄Ga₁₆ alloy by directional solidification technique. Interestingly, the Griffiths phase was found in Co-V-Ga alloy for the first time. Using the DSC curve and the inverse DC susceptibility (χ⁻¹) in the high temperature region, the spontaneous magnetization revealed the existence of Griffiths phase in the high temperature region. And then, according to Arrott plot, the phase transition was determined around the T_C. Modified form of the Bean-Rodbell model, considering a shape memory alloy material with compressibility, spin and spin density, one defines the parameter ε, which is 0.26, (ε < 1), further confirmed the transition type around T_C. At low temperature, spin wave excitation (Heisenberg ferromagnetic type) was used to study the dependence of spontaneous magnetization on temperature to investigate half metallicity.