Sublattice spin reversal and field induced $Fe^{3+}$ spin-canting across the magnetic compensation temperature in $Y_{1.5}Gd_{1.5}Fe_{5}O_{12}$ rare-earth iron garnet
Manik Kuila, Jose Renato Linares Mardegan, Akhil Tayal, Sonia Francoual, V. Raghavendra Reddy
In the present work $Fe^{3+}$ sublattice spin reversal and $Fe^{3+}$ spin-canting across the magnetic compensation temperature ($T_{Comp}$) are demonstrated in polycrystalline $Y_{1.5}Gd_{1.5}Fe_{5}O_{12}$ (YGdIG) by means of in-field $^{57}Fe$ M$\ddot{o}$ssbauer spectroscopy measurements. Corroborating in-field $^{57}Fe$ M$\ddot{o}$ssbauer measurements, both $Fe^{3+}$ & $Gd^{3+}$ sublattice spin reversal has also been manifested with x-ray magnetic circular dichroism (XMCD) measurement in hard x-ray region. Moreover from in-field $^{57}Fe$ M$\ddot{o}$ssbauer measurements, estimation and analysis of effective internal hyperfine field ($H_{eff}$), relative intensity of absorption lines in a sextet elucidated unambiguously the signatures of $Fe^{3+}$ spin reversal, their continuous transition and field induced spin-canting of $Fe^{3+}$ sublattices across $T_{Comp}$. Further, Fe K- (Gd $L_{3}$-) edge XMCD signal is observed to consist of additional spectral features, those are identified from $Gd^{3+}$ ($Fe^{3+}$) magnetic ordering, enabling us the extraction of both the sublattices ($Fe^{3+}$ & $Gd^{3+}$) information from a single edge analysis. The evolution of the magnetic moments as a function of temperature for both magnetic sublattices extracted either at the Fe K- or Gd $L_3$-edge agree quite well with values that are extracted from bulk magnetization data of YGdIG and YIG ($Y_{3}Fe_{5}O_{12}$). These measurements pave new avenues to investigate how the magnetic behavior of such complex system acts across the compensation point.
Compensation-Like Temperature and Spin-Flip Switch in Strained Thulium Iron Garnet Thin Films: Tuning Sublattice Interactions for Ferrimagnetic Spintronics
Switching of an antiferromagnet controlled by spin canting in a laser-induced hidden phase
Ioffe Institute（约费研究所）；Scientific-Practical Materials Research Centre, NAS of Belarus（白俄罗斯国家科学院科学实践材料研究中心）；Laboratory ”Magnetic Metamaterials”, Saratov State University（萨马拉国立大学磁超材料实验室）
Emergence of a spin Hall topological Hall effect in the non-collinear phase of the ferrimagnetic insulator terbium-iron garnet
Institute of Physics, Johannes Gutenberg University Mainz（美因茨约翰内斯·古腾堡大学物理研究所）；Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C-1), Forschungszentrum Jülich GmbH（于利希研究中心格恩斯特·鲁斯卡电子显微与光谱中心（ER-C-1））；Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology（挪威科技大学量子自旋电子学中心）
Giant widening of interface magnetic layer in almost compensated iron garnet
在沿易磁化方向取向的磁场中，双子晶格亚铁磁体经历从共线到倾斜的磁相转变。本工作利用磁光法拉第效应研究了生长在Gd $_3$ Ga $_5$ O $_{12}$衬底上的补偿铁石榴石（Lu $_{3-{\rm{x}}}$ Bi $_{\rm{x}}$）（Fe $_{5-{\rm{y}}-{\rm{z}}}$ Ga $_{\rm{y}}$ Al $_{\rm{z}}$）O $_{12}$薄膜的磁光跃迁。在补偿温度附近，观察到具有复杂形状的过渡的前体。使用一个特殊的样品具有可变的厚度，我们证明了前体的界面起源。钆从衬底扩散到膜中形成具有增强的磁化的薄混合层。它在薄膜中诱导出扩展的不均匀磁结构。由于混合磁性层的易面各向异性，出现了两个台阶形状的前体。我们强调，在接近补偿温度时，薄膜中的非均匀磁化分布的有效宽度极大地增长。
Double magnetic transition, complex field-induced phases, and large magnetocaloric effect in the frustrated garnet compound Mn$_{3}$Cr$_{2}$Ge$_{3}$O$_{12}$
Spin Disorder and Magnetic Anisotropy in Fe3O4 Nanoparticles
我们研究了具有中值粒径$\left<d\right>=8$ $nm$的葡聚糖包覆的磁铁矿（Fe $_3$ O $_4$）纳米颗粒的磁性行为。磁化曲线和现场穆斯堡尔谱测量表明，颗粒的磁矩$M_S$是远远小于块体材料。然而，我们没有发现在高磁场下磁不可逆性或非饱和行为的证据，通常与自旋倾斜有关。来自不同技术的磁各向异性$K_{eff}$的值表明，表面或形状的贡献可以忽略不计。这些粒子具有有序的A和B亚晶格的类块体亚铁磁结构，但几乎补偿了磁矩。阻塞温度与频率和外加场的依赖关系，$T_B(H,ω)$，表明所观察到的非单调行为是由粒子间相互作用的强度。
Spin reorientation of the Fe moments in Eu$_{0.5}$Ca$_{0.5}$Fe$_{2}$As$_{2}$: Evidence for a strong interplay of Eu and Fe magnetism
用互补极化和非极化单晶中子衍射方法研究了Eu $_{0.5}$ Ca $_{0.5}$ Fe $_{2}$ As $_{2}$的温度相关磁性结构。在A型反铁磁（AFM）结构中，当Eu位被等价的Ca $^{2+}$稀释50%时，在低于$\mathit{T_{Eu}}$ = 10 K的温度下，Eu亚晶格仍然是长程有序的.在2.5 K时，Eu $^{2+}$自旋的磁矩大小为6.74（4）$μ_{B}$. Fe亚晶格在$\mathit{T_{SDW}}$ = 192（2）K时经历自旋密度波转变，并在$\mathit{T_{Eu}}$上方显示面内AFM结构。而在2.5 K时，Fe的$^{2+}$矩在与$\mathit{ab}$平面成14（4）°的倾斜AFM结构中是有序的.低于Eu的AFM有序温度的Fe的自旋重取向提供了Eu $_{0.5}$ Ca $_{0.5}$ Fe $_{2}$ As $_{2}$中两个磁性亚晶格之间强相互作用的直接证据。
Spin dynamics of the quantum dipolar magnet Yb$_3$Ga$_5$O$_{12}$ in an external field
我们研究了镱镓石榴石Yb $_{3}$ Ga $_{5}$ O $_{12}$在顺磁相以上的假设的磁性转变在$T_λ \approx 54$ mK。我们的研究将磁化率和比热测量与中子散射实验和理论计算相结合。低于500 mK，弹性中子响应在动量空间中强烈地达到峰值。与此同时，非弹性谱发展平坦的激励模式。在磁场中，最低能量分支遵循塞曼位移，根据场依赖的比热数据。在小的磁场中证明了自旋偏离场方向的中间态。在2 T的磁场中，总磁化强度几乎饱和，并且通过仅考虑偶极-偶极相互作用的自旋波计算很好地再现了测量的激发谱。由磁化率测量得到的小的正居里-外斯温度也由偶极自旋模型解释。总之，我们的结果表明，Yb $_{3}$ Ga $_{5}$ O $_{12}$是一个量子偶极磁体。
