The Origin of the Spin Reorientation Transition in Gd2–xHoxFeCrO6 (x = 0.5) Double Perovskite

Abstract

The influence of rare-earth Ho³⁺ ions at the A-site (Gd³⁺) of Gd₂FeCrO₆ (GFCO) is investigated. The crystal structure, Raman modes and magnetic properties of the parent Gd₂FeCrO₆ (GFCO) and Gd_2–xHo_xFeCrO₆ (GHFCO) with x=0.5 are reported. The compounds Gd₂FeCrO₆ (GFCO) and Gd_1.5Ho_0.5FeCrO₆ (GHFCO), synthesised via the solid-state reaction method, crystallise in an orthorhombic structure with the Pbnm space group. The difference in the ionic radii between Ho and Gd gives rise to a shift in the highly intense XRD peak of GHFCO, and the corresponding changes represent a double perovskite structure. The observed 10 Raman-active modes further confirm the orthorhombic structure, and a higher wavenumber shift is observed in GHFCO. An increase in the Néel transition to 235 K is observed in GHFCO compared to the parent GFCO, whose T_N is ~190 K. GHFCO exhibits strong bifurcation, evidenced by the ZFC/FC curves, but for GFCO there exists an overlap between the curves. M-H loops were traced at 300 and 10 K for GFCO and GHFCO. Most importantly, spin reorientation is observed in GHFCO at low temperatures.

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