Multiple spin reorientation transitions in Ga3+-substituted DyCrO3

Abstract

Single-phase DyCr_1−xGa_xO₃ (0 ≤ x ≤ 0.5) samples were synthesized successfully by a sol–gel method. Magnetic measurement results indicate that the Ga³⁺-substituted samples exhibit multiple spin reorientation transitions (Γ₂ → Γ₄ → Γ₂ → Γ₁), whereas the pure DyCrO₃ sample does not exhibit any spin reorientation transition. This is the first time that three types of spin reorientation transitions have been observed simultaneously in a rare-earth orthochromite sample. The stability of the spin reorientation transitions under cooling field was also investigated. Additionally, the temperature dependent inverse susceptibility exhibits a downward deviation from Curie–Weiss behavior above Néel temperature, suggesting the presence of the Griffiths phase in the Ga³⁺-substituted samples. The occurrence of such rich magnetic structures can be attributed to the fact that Ga³⁺ substitution weakens the exchange interaction between Cr³⁺ ions as well as between rare-earth ions (R³⁺) and Cr³⁺ ions more effectively in DyCrO₃. Notably, Dy³⁺ possesses the highest effective magnetic moment among all rare-earth ions, which may enhance the sensitivity of the magnetic properties to substitutions. The multiple spin reorientation transitions make DyCr_1−xGa_xO₃ promising candidate materials for magnetic switching devices.