标题： 室温铁磁性由高价阳离子 V$^{+5}$/V$^{+4}$替换 SrFeO$_{3-δ}$引起 显示英文标题

标题： Room temperature ferromagnetism induced by high valence cation V$^{+5}$/V$^{+4}$ substitution in SrFeO$_{3-δ}$

摘要： 非磁性钒（V）掺杂在螺旋反铁磁材料SrFeO$_{3-\delta}$（SFO）中的结构和磁性效应被研究，重点在于铁位点最多3%的替代。 从X射线衍射（XRD）和拉曼光谱的结构分析，以及声子模式计算的支持下，揭示出纯SFO以四四方-正交相混合存在，而掺杂V的样品则表现出一种新兴的立方相，同时保持四四方对称性。 磁滞回线（M-H）显示在反铁磁基质中表现出显著的铁磁行为，即使在室温下也持续存在。 温度依赖的磁化测量表明，奈尔温度（TN）从70K降至55K，同时场冷（FC）和零场冷（ZFC）数据中的磁化差异增加，反映了由于竞争的铁磁/反铁磁交换相互作用导致的磁性挫败增强。 X射线光电子能谱（XPS）和X射线吸收近边结构（XANES）分析显示，Fe$^{3+}$和V$^{5+}$状态上升，影响了氧空位分布，并在XRD和拉曼结果中观察到相应的结构变化。 多价态的Fe$^{3+}$/Fe$^{4+}$和 V$^{4+}$/V$^{5+}$状态增强双交换（DE）和超交换（SE）相互作用（Fe$^{3+}$-O-Fe$^{4+}$和 Fe$^{3+}$-O-V$^{5+}$），促进铁磁性。 频率依赖的磁化研究显示一个细微的磁化率峰位移，表明钒掺杂样品中存在自旋玻璃样行为。 显示英文摘要

摘要： The structural and magnetic effects of non-magnetic vanadium (V) doping in helimagnetic SrFeO$_{3-\delta}$ (SFO) are investigated, focusing on up to 3% substitution at the Fe site. Structural analysis from X-ray diffraction (XRD) and Raman spectroscopy, supported by phonon mode calculations, reveals that pure SFO exists as a mixed tetragonal-orthorhombic phase, while V-doped samples exhibit an emerging cubic phase alongside tetragonal symmetry. Magnetic hysteresis (M-H) loops show notable ferromagnetic behavior within the antiferromagnetic matrix, persisting even at room temperature. Temperature-dependent magnetization measurements indicate a Neel temperature (TN ) shift from 70K to 55K, along with increased magnetization differences in field-cooled (FC) and zero field-cooled (ZFC) data, reflecting heightened magnetic frustration due to competing FM/AFM exchange interactions. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) analyses reveal a rise in Fe$^{3+}$ and V$^{5+}$ states, affecting oxygen vacancy distributions and corresponding structural shifts seen in XRD and Raman results. The multivalent Fe$^{3+}$/Fe$^{4+}$ and V$^{4+}$/V$^{5+}$ states enhance double-exchange (DE) and super-exchange (SE) interactions (Fe$^{3+}$-O-Fe$^{4+}$ and Fe$^{3+}$-O-V$^{5+}$), promoting ferromagnetism. Frequency-dependent magnetization studies display a subtle susceptibility peak shift, indicating spin-glass-like behavior in V-doped samples.