We report a novel critical exponent delta=3/2 of magnetization curves M=H^{1/delta} near the ferromagnetic quantum phase transitions of Sr1-xAxRuO3 (A = Ca, La0.5Na0.5, and La), which the mean field theory of the Ginzburg-Landau-Wilson type fails to reproduce. The effect of dirty ferromagnetic spin fluctuations might be a key.
Tunnel barrier enhanced voltage signals generated by magnetization precession of a single ferromagnetic layer
我们报告的电检测的磁化动力学在Al/AlOx/Ni 80 Fe 20/Cu隧道结，其中Ni 80 Fe 20铁磁层被带入旋进铁磁共振（FMR）条件下。由旋进铁磁体产生的跨结的直流电压与当这种类型的多层结构中的接触是欧姆的时观察到的电压信号相比增强了大约一个数量级。我们讨论了这种现象的磁自旋泵的关系，并推测其他可能的潜在机制负责增强的电信号。
Geometrical control of the magnetization direction in high aspect-ratio PdNi ferromagnetic nano-electrodes
我们提出了一个研究的电子束蒸发的Pd 0.4 Ni 0.6合金薄膜的扩展膜的不同厚度的铁磁共振测量和各向异性磁阻测量光刻图案的高深宽比的铁磁电极，分别通过。结果表明，磁化的方向强烈地依赖于电极的横向尺寸，从延伸膜的面内磁化转变为电极宽度低于2-3微米的面外磁化，对于100 nm宽的纳米电极达到58度的面外磁化。
The $S=1/2$ distorted diamond spin chain with the anisotropic ferromagnetic interaction is investigated using the numerical diagonalization and the level spectroscopy analysis. It is known that the system exhibits a plateau of the magnetization curve at the 1/3 of the saturation. The present study indicates that as the anisotropy is varied the quantum phase transition occurs between two different mechanisms of the 1/3 magnetization plateau. The phase diagram with respect to the anisotropy and the ferromagnetic coupling is also presented.
Materials with zero energy band gap display intriguing properties including high sensitivity of the electronic band structure to external stimulus such as pressure or magnetic field. An interesting candidate for zero energy band gap are Weyl nodes at the Fermi level EF. A prerequisite for the existence of Weyl nodes is to either have inversion or time reversal symmetry broken. Weyl nodes in systems with broken time reversal symmetry are ideal to realize the tunability of the electronic band structure by magnetic field. Theoretically, it has been shown that in ferromagnetic Weyl materials, the …
We study the critical behavior of dc magnetization in the uranium ferromagnet URhSi around the paramagnetic to ferromagnetic phase transition at T_C~ 10 K with a modified Arrott plot, a Kouvel-Fisher plot, the critical isotherm analysis and the scaling analysis. URhSi is isostructural to uranium ferromagnetic superconductors URhGe and UCoGe. The critical exponent beta for the temperature dependence of the spontaneous magnetization below TC, gamma for the magnetic susceptibility, and delta for the magnetic isotherm at T_C in URhSi have been determined as beta = 0.300 +- 0.002, gamma = 1.00 +- 0…
The phenomenon of ferromagnetic resonance (FMR) is still being exploited for determining the magnetocrystalline anisotropy constants of magnetic materials. We show that one can also determine accurately the saturation magnetization of the sample using results of FMR experiments after taking into account the relationship between resonance frequency and curvature of the spatial distribution of free energy at resonance. Specifically, three examples are given of calculating saturation magnetization from FMR data: we use historical Bickford's measurements from 1950 for bulk magnetite, Liu's measure…
Current-driven magnetization decrease in single crystalline ferromagnetic manganese oxide
本文研究了铁磁锰氧化物$\Pr_{0.8}$ Ca $_{0.2}$ MnO $_3$的电、磁特性。在相同的阈值电流下，观察到磁化强度的显著降低，其中V-I特性出现非线性。这种行为不能理解的框架内的解释图片通常调用的非线性的其他锰氧化物。相反，与自旋电子学特征的类比可能是有用的，实验特征似乎与电流激发自旋波一致。这提供了体系统的示例，其中自旋极化电流引起磁化的宏观变化。
We have studied the magnetization process of the new insulating ferromagnetic semiconductor (Al,Fe)Sb by means of x-ray magnetic circular dichroism. For an optimally doped sample with 10% Fe, a magnetization was found to rapidly increase at low magnetic fields and to saturate at high magnetic fields at room temperature, well above the Curie temperature of 40 K. We attribute this behavior to the existence of nanoscale Fe-rich ferromagnetic domains acting as superparamagnets. By fitting the magnetization curves using the Langevin function representing superparamagnetism plus the paramagnetic lin…
Flexible ferromagnetic rings are spin-chain magnets, in which the magnetic and mechanical subsystems are coupled. The coupling is achieved through the tangentially oriented anisotropy axis. The possibility to operate the mechanics of the nanomagnets by controlling their magnetization is an important issue for the nanorobotics applications. A minimal model for the deformable curved anisotropic Heisenberg ferromagnetic wire is proposed. An equilibrium phase diagram is constructed for the closed loop geometry: (i) A vortex state with vanishing total magnetic moment is typical for relatively large…
A correct general formula for the spin current through an interacting quantum dot coupled to ferromagnetic leads with magnetization at an arbitrary angle $θ$ is derived within the framework of the Keldysh formalism. Under asymmetric conditions, the spin current component J_{z} may change sign for $0<θ<π$. It is shown that the spin current and spin tunneling magnetoresistance exhibit different angle dependence in the free and Coulomb blockade regimes. In the latter case, the competition of spin precession and the spin-valve effect could lead to an anomaly in the angle dependence of the spin cur…
