Spin reorientation and multi-physical field control in high-entropy orthoferrite single crystals

Abstract

The high-entropy design strategy offers a route to control the spin order in rare-earth orthoferrites (RFeO3). In this work, a high-entropy perovskite single crystal of Y0.2Nd0.2Sm0.2Er0.2Tm0.2FeO3 (5RFeO) was grown using the optical floating zone method. Its high crystalline quality and precise orientation were confirmed by x-ray and Laue diffraction. The effects of temperature, magnetic field, and hydrostatic pressure on the spin reorientation (SR) behavior were systematically investigated. Our measurements reveal that under low magnetic fields, the crystal exhibits a Γ4 → Γ4 + Γ2 → Γ2 transition sequence within the temperature range of 125–160 K. The applied magnetic field suppresses the SR, broadening the transition temperature window. Furthermore, hydrostatic pressure above ∼0.80 GPa reconstructs the transition pathway in a manner that points to a Γ1-like intermediate state, leading to a complex and multi-step transition sequence. The magnetic moment along the b axis remains insensitive to both the magnetic field and pressure. This study demonstrates the tunability of spin reorientation to multiple physical stimuli in a chemically disordered high-entropy system, elucidates the underlying spin structure evolution mechanism, and highlights the application potential of such high-entropy orthoferrites in spin-based devices.