论文标题
铁酸钠Na2fesbo5的合成和表征一维抗铁磁链链具有自旋玻璃基态
Synthesis and Characterization of Sodium Iron Antimonate Na2FeSbO5 One-Dimensional Antiferromagnetic Chain Compound with a Spin Glass Ground State
论文作者
论文摘要
合成并在结构上进行了一种新的氧化氧化物抗吡甲酸钠，Na2fesbo5，其静态和动态磁性能通过DC和AC磁敏感性，磁化，特定的热量，电子自旋共振（ESR）和Moessbauer测量和Moessbauer测量和从d d d d d d d d d d d d d d d d d d d dc进行了实验性研究。 The resulting single-crystal structure (a = 15.6991(9) A; b = 5.3323 (4) A; c = 10.8875(6) A; S.G. Pbna) consists of edge-shared SbO6 octahedral chains, which alternate with vertex-linked, magnetically active FeO4 tetrahedral chains. 57FE Moessbauer光谱证实了在扭曲的四面体氧气配位中存在高旋转Fe3+（3d5）离子。磁化易感性和比热数据表明，Na2fesbo5中没有远程磁性顺序降至2 K，但是AC磁敏感性无意义地证明了旋转玻璃型行为，在TF1处唯一的两步式冻结了约80 K和TF2，约35 k和TF2，约35k。大约35 k的磁性磁性超纤维分裂，在57fe moessbauer spectra of Moessbauer spectra overs ting* theft teff2 tf2 tf2 <下面<下面<下面<下面* k（t）。 T*（TF1 <T <T*）下方的光谱表现出由临界自旋波动引起的弛豫行为，表明存在短距离相关性。离子自旋松弛的随机模型用于解释低于冰点温度以下的Moessbauer光谱的形状。 ESR数据进一步支持了复杂的缓慢动力学，揭示了两种不同的吸收模式，可能与旋转链的有序和无序段有关。数据暗示Na2fesbo5的自旋群集基态。
A new oxide, sodium iron antimonate, Na2FeSbO5, was synthesized and structurally characterized, and its static and dynamic magnetic properties were comprehensively studied both experimentally by dc and ac magnetic susceptibility, magnetization, specific heat, electron spin resonance (ESR) and Moessbauer measurements, and theoretically by density functional calculations. The resulting single-crystal structure (a = 15.6991(9) A; b = 5.3323 (4) A; c = 10.8875(6) A; S.G. Pbna) consists of edge-shared SbO6 octahedral chains, which alternate with vertex-linked, magnetically active FeO4 tetrahedral chains. The 57Fe Moessbauer spectra confirmed the presence of high-spin Fe3+ (3d5) ions in a distorted tetrahedral oxygen coordination. The magnetic susceptibility and specific heat data show the absence of a long-range magnetic ordering in Na2FeSbO5 down to 2 K, but ac magnetic susceptibility unambigously demonstrates spin-glass-type behavior with a unique two-step freezing at Tf1 about 80 K and Tf2 about 35 K. Magnetic hyperfine splitting of 57Fe Moessbauer spectra was observed below T* about 104 K (Tf1 < T*). The spectra just below T* (Tf1 < T < T*) exhibit a relaxation behavior caused by critical spin fluctuations, indicating the existence of short-range correlations. The stochastic model of ionic spin relaxation was used to account for the shape of the Moessbauer spectra below the freezing temperature. A complex slow dynamics is further supported by ESR data revealing two different absorption modes presumably related to ordered and disordered segments of spin chains. The data imply a spin-cluster ground state for Na2FeSbO5.
