Field induced metamagnetic transitions in quasi-one-dimensional Ising spin chain CoV2O6

•Physical properties of α-CoV2O6 and γ-CoV2O6 are compared and contrasted in random polycrystalline samples.•We investigate specific heat and thermal expansion for both phases of CoV2O6•Field induced peak in specific heat has been observed in α-CoV2O6.•α-CoV2O6 exhibits large positive magnetostriction.

We have investigated the temperature and magnetic field dependence of magnetization (M), specific heat (Cp), and relative sample length change (ΔL/L0ΔL/L0) for understanding the field-induced metamagnetic transitions in quasi-one-dimensional monoclinic (α phase) and triclinic (γ phase) CoV2O6 spin chains. With the application of external magnetic field, a sharp peak emerges in Cp(T  ) below TN=15K in α   phase and a hump-like feature appears above TN=6.5K in γ phase due to the field-induced ferrimagnetic and ferromagnetic transitions, respectively. Strong field dependence of linear thermal expansion and large positive magnetostriction have been observed in α phase. Though magnetization data indicate strong spin–orbit coupling for both phases, other measurements show that this effect is very weak for the γ phase.