论文标题
当地旋转的中子衍射证据，弱的jahn-teller失真和磁补偿，ti $ _ {1-x} $ mn $ _ {x} $ _2
Neutron Diffraction Evidence for Local Spin Canting, Weak Jahn-Teller Distortion, and Magnetic Compensation in Ti$_{1-x}$Mn$_{x}$Co$_2$O$_4$ Spinel
论文作者
论文摘要
在MN上报告了一项使用中子衍射和磁化能力的系统研究所有Jahn-Teller Active离子的$ t $ o $ _6 $ contahedral $ t $ = mn $^{3+} $，ti $^{3+} $和co $^{3+} $，由X射线光电子光谱证实。之所以选择两种特定的成分（$ x $ = 0.2和0.4），是因为它们具有独特功能：非结合YAFET-KITTEL类型订购，而使用$ {c/a} $ <$ <$ <$ <$ <$ <$ <$ <$ <$ <$ <$ d_c $ $ d_c $（$ t_b $ -o）比equare $ d_ $ d_ $ d_ ab} $ {c/a} $ <$ <$ <$ <$ < $ e_g $ mn $^{3+} $ ions $ d_ {x^2-y^2} $和$ d_ {z^2} $。对于$ x $ = 0.4，$ t_b $ o $ $ _6 $ contahedra中的失真更强，而$ x $ = 0.2，因为三价MN的含量较高。 $ x $ = 0.4和$ x $ = 0.2套件的效率分别为110.3和78.2 k，这是由于阳离子的不等磁矩，其中Ti $^{3+} $，Mn $^{3+} $，以及CO $ $^{3+} $四面体部位。另外，可以观察到垂直于铁磁成分的弱抗铁磁成分。对静态和动态磁敏感性的分析与热容量数据相结合的分析表明，在$ t_ {comp} $ t_ {comp} $ = 25.4 k中的磁补偿现象，$ x $ = 0.2，$ x $ = 0.4的重新输入旋转玻璃行为具有freezing温度$ \ sim $ \ sim $ 110.1 k的效果。 $ t_ {comp} $具有其大小，具体取决于外部磁场和冷却协议的方向。
A systematic study using neutron diffraction and magnetic susceptibility are reported on Mn substituted ferrimagnetic inverse spinel Ti$_{1-x}$Mn$_{x}$Co$_2$O$_4$ in the temperature interval 1.6 K $\leq$ $T$ $\leq$ 300 K. Our neutron diffraction study reveals cooperative distortions of the $T$O$_6$ octahedral for all the Jahn-Teller active ions $T$ = Mn$^{3+}$, Ti$^{3+}$ and Co$^{3+}$, which are confirmed by the X-ray photoelectron spectroscopy. Two specific compositions ($x$ = 0.2 and 0.4) have been chosen because of their unique features: noncollinear Yafet-Kittel type ordering, and weak tetragonal distortion with ${c/a}$ $<$ 1, in which the apical bond length $d_c$($T_B$-O) is longer than the equatorial $d_{ab}$($T_B$-O) due to the splitting of the $e_g$ level of Mn$^{3+}$ ions into $d_{x^2-y^2}$ and $d_{z^2}$. For $x$ = 0.4, the distortion in the $T_B$O$_6$ octahedra is stronger as compared to $x$ = 0.2 because of the higher content of trivalent Mn. Ferrimagnetic ordering in $x$ = 0.4 and $x$ = 0.2 sets in at 110.3 and 78.2 K, respectively due to the unequal magnetic moments of cations, where Ti$^{3+}$, Mn$^{3+}$, and Co$^{3+}$ occupying the octahedral, whereas, Co$^{2+}$ sits in the tetrahedral site. In addition, weak antiferromagnetic component could be observed lying perpendicular to the ferrimagnetic component. The analysis of static and dynamic magnetic susceptibilities combined with the heat-capacity data reveals a magnetic compensation phenomenon at $T_{COMP}$ = 25.4 K in $x$ = 0.2 and a reentrant spin-glass behaviour in $x$ = 0.4 with a freezing temperature $\sim$110.1 K. The compensation phenomenon is characterized by sign reversal of magnetization and bipolar exchange bias effect below $T_{COMP}$ with its magnitude depending on the direction of external magnetic field and the cooling protocol.
