Thermal expansion of the quasi two-dimensional magnetic layered compound BaNi2V2O8 under magnetic fields along c-axis

The quasi two-dimensional magnetic BaNi2V2O8 is studied by using high-resolution thermal expansion in magnetic fields up to 10T applied along the c-axis. A slight increase of about 1% of the three-dimensional antiferromagnetic ordering temperature TN is observed at 10T. Positive and negative pressure dependencies of TN, respectively, are inferred from the thermal expansion alpha(T) for pressures applied along the a- and c-axes.