ABSTRACT

The synthesis of GdFe_0.5Cr_0.5O₃ by sol-gel method was reported, and the cooling process of the sample was studied by Mössbauer spectroscopy. The Mössbauer spectra at room temperature reflect the characteristics of GdFe_0.5Cr_0.5O₃ with orthogonally distorted perovskite structure, indicating that its Fe³⁺ is a triangular or tetragonal distorted octahedron symmetric structure. With the decrease of temperature, the isomer shift and quadrupole splitting increase. The spectral transition from the doublet state at 250 K to the sextet state at 120 K reflects the magnetic phase transition in this temperature range. The observed magnetic field is a super-transferred hyperfine field (STHF) formed by the superexchange mechanism of oblique antiferromagnetic ordered Cr atoms.

摘要

报道了采用溶胶-凝胶法合成GdFe _0.5 Cr _0.5 O ₃，并通过穆斯堡尔光谱研究了样品的冷却过程。室温下的穆斯堡尔谱反映了具有正交畸变钙钛矿结构的 GdFe _0.5 Cr _0.5 O ₃的特性，表明其 Fe ³⁺是三角形或四边形扭曲八面体对称结构。随着温度的降低，异构体位移和四极分裂增加。从 250 K 的双重态到 120 K 的六重态的光谱转变反映了该温度范围内的磁相变。观测到的磁场是由倾斜的反铁磁有序铬原子的超交换机制形成的超转移超精细场（STHF）。