Pressure effect and magnetodielectric behavior of Néel-type skyrmion VOSe₂O₅

The external pressure effects on a polycrystalline sample of polar Néel-type skyrmion VOSe₂O₅ has been investigated. Using the temperature (T) and magnetic field (H)-dependent ac susceptibility measurements, the H - T magnetic phase diagram for skyrmion boundaries has been successfully established. From DC magnetization, VOSe₂O₅ undergoes two magnetic ordering at T_N1 = 7. 45 K and T_N2 = 3.3 K. Interestingly, T_N1 is increased, while the T_N2 is decreased with application of external pressure (P). A four-fold enhancement of the skyrmion zone in the H-T phase diagram located in 7.2 K ? T ? 7.4 K and 16.7 Oe ? H ? 46.5 Oe at ambient pressure is enhanced to 7.4 K ? T ? 8.05 K and 14.5 Oe ? H ? 61.3 Oe at 14.2 kbar. Further, T and H-dependent dielectric (e¢) data indicate e¢ anomalies at T_N1 and T_N2 with the magnetoelectric coupling below T_N1. Density function theory along with TB2J calculations, was employed to explore the anisotropic exchange ()as well as the Dzyaloshinskii–Moriya interaction () parameters. A significant modulation of and was found and ascribed to be a possible source for enhancing the skyrmion phase under external pressure.