Giant exchange bias effect in YCo$_{\mathrm{0.25}}$Mn$_{\mathrm{0.75}}$O$_{\mathrm{3}}$ compound according to change of ratio by additional Mn ions

Recently studied on exchange bias (EB) phenomena in Y$_{\mathrm{2}}$CoMnO$_{\mathrm{6}}$ reveals interfacial exchange coupling between Mn$^{\mathrm{4+}}$-O-Mn$^{\mathrm{4+}}$, Co$^{\mathrm{2+}}$-O-Co$^{\mathrm{2+}}$ antiferromagnetic (AFM) ordering induced by antisite defect and Co$^{\mathrm{2+}}$-O-Mn$^{\mathrm{4+\thinspace }}$ferromagnetic (FM) ordering, while we approached EB effect by additional Mn ion according to change of ratio between Co and Mn ions, successfully made YCo$_{\mathrm{0.25}}$Mn$_{\mathrm{0.75}}$O$_{\mathrm{3}}$ compound. Spin-glass behavior is observed because of complex magnetic properties. We observed that the week FM hysteresis loop is at 2 K, giant exchange bias field, H$_{\mathrm{EB}}$ \textasciitilde 13 kOe, was observed at 2 K in measuring field range ±15 kOe after applied field cooled (FC) in 40 kOe. The observed exchange bias effect reveals the strong dependence on cooling magnetic fields, measuring fields, and temperature. We suggest that the giant EB effect would originate from the interfacial pinning of exchange couplings between not only FM and AFM ordering but also FM and SG areas generated due to Mn$^{\mathrm{3+}}$-O-Mn$^{\mathrm{3+}}$ AFM ordering created by additional Mn ion.