Manipulation of spin reorientation in Nd0.6Y0.4FeO3 single crystals by magnetic field and hydrostatic pressure

This work investigates spin reorientation in Nd0.6Y0.4FeO3 single crystals under temperature, magnetic field and hydrostatic pressure. High-quality crystals were grown by the optical floating zone method. Temperature-dependent magnetization reveals a continuous Γ4→Γ4+Γ2→Γ2 transition upon cooling, with the transition region occurring at 50-150 K. Magnetic field regulation exhibits strong anisotropy, wherein the field-induced Γ4→Γ2 transition occurs along the a-axis above a temperature-dependent critical field, while the b-axis remains antiferromagnetic and the c-axis evolves from weak ferromagnetic to antiferromagnetic. Remarkably, hydrostatic pressure reconstructs the transition pathway. Above ~0.63 GPa, the normally unstable Γ1 antiferromagnetic phase emerges as a thermodynamic intermediate state, transforming the simple Γ4→Γ2 sequence into a multi-step process of Γ4→Γ4+Γ1→Γ4+Γ1+Γ2→Γ1+Γ2→Γ2. This pathway reconstruction is evidenced by decoupled a- and c-axis magnetic responses under pressure. A pressure-temperature magnetic phase diagram is established, visualizing this pressure-induced pathway evolution. This study demonstrates lattice-strain-spin coupling in manipulating spin reorientation, offering insights into magnetic interactions in rare-earth orthoferrites for spintronic applications.