Absence of long-range V-V dimer and magnetic orderings in high-entropy (MgMnCoNiCu)VO

Yamamoto, Hajime*; Tsuji, Takuya  ; Matsumura, Daiju   ; 16 of others*

V-V dimerization in ilmenite-type vanadium oxides is an intriguing phenomenon that induces structural and metal-to-insulator transitions. Herein, we report the high-pressure synthesis, crystal structure, and electronic states of high-entropy ilmenite-type (MgMnCoNiCu)VO. Although all the parent ilmenite-type compounds exhibit triclinic () symmetry, this compound crystallizes in a rhombohedral () structure, indicating the absence of V-V dimer ordering. The temperature dependence of the resistivity below room temperature follows a variable-range hopping conduction mechanism, suggesting the presence of short-range V-V dimer ordering. Magnetic susceptibility and heat capacity measurements revealed multi-step spin-glass transitions. This study demonstrates that a high-entropy composition hinders electronic and magnetic long-range ordering due to severe lattice distortions and competition between magnetic exchange interactions.