Ultrafast non-thermal manipulation of magnetization by light relies on either indirect coupling of the electric field component of the light with spins via spin-orbit interaction or direct coupling between the magnetic field component and spins. Here we propose a scenario for coupling between the electric field of light and spins via optical modification of the exchange interaction, one of the strongest quantum effects with strength of 103 Tesla. We demonstrate that this isotropic opto-magnetic effect, which can be called inverse magneto-refraction, is allowed in a material of any symmetry. Its existence is corroborated by the experimental observation of terahertz emission by spin resonances optically excited in a broad class of iron oxides with a canted spin configuration. From its strength we estimate that a sub-picosecond modification of the exchange interaction by laser pulses with fluence of about 1 mJ cm−2 acts as a pulsed effective magnetic field of 0.01 Tesla.

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Nano‐crystalline LaFeO3 was synthesized by a sol–gel auto‐combustion method from a mixed aqueous solution of lanthanum and iron nitride, using citric acid as the fuel. Powder X‐ray diffraction and TG/DTA analysis show that the LaFeO3 crystallites can be directly obtained by the sol–gel combustion process, without any other undesired phase. The results of SEM and TEM reveal that the as‐burnt samples and powder calcined at 700 °C are agglomerated with particle size in the range of 25–50 nm and 60–80 nm, respecitvely. The M (T) and M (H) curves measurements show the existence of a weak ferromagnetism and the mainly anti‐ferromagnetic ordering of the spins in the calcined sample. Compared with the powder calcined at 600 °C and 700 °C, the as‐burnt LaFeO3 exhibits much stronger ferromagnetic behavior, with larger magnetization and smaller coercive field. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Efficient and stable electromagnetic-wave (EMW) absorption materials have attracted great attention in the field of reducing microwave pollution. Herein, FeCoNiCuTi x high-entropy alloys (HEAs) as electromagneticwave absorbing materials were prepared by a high-energy ball-milling method. The as-milled HEA powders presented a flaky shape with a high aspect ratio. Impedance matching was efficiently optimized by severe lattice distortion, which was caused by Ti incorporation. The introduced plentiful defects in FeCoNiCuTi x HEAs provided abundant polarization sites for dielectric loss. By tuning Ti contents, FeCoNiCuTi 0.2 HEAs delivered excellent EMW absorption performances. The maximal reflection loss (RL max ) values reached −47.8 dB at 10.86 GHz as thin as 2.16 mm, and the widest bandwidth was 4.76 . Furthermore, the introduction of Ti enhanced corrosion resistance via increasing the charge transfer resistance of a passivated film. Those characteristics of FeCoNiCuTi x HEAs made these materials a practical gigahertz-range EMW absorber. Additionally, our findings provided a facile and tunable strategy for designing EMW absorbing materials, which was aimed at lightweight, highly efficient absorption, and resistance to harsh environments.

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YFeO 3 and other rare earth substituted crystals with distorted orthorhombic pervoskite-like structure (space group, Pbnm) have attracted much attention due to their remarkable magnetic properties of primary significance for technological applications. In the present work, the floating zone growth of YFeO 3 crystals has been systematically investigated and high quality YFeO 3 crystal was obtained by optimized process. The magnetic properties of YFeO 3 crystal were investigated, and it indicated the high magneto-optical property in YFeO 3 crystals with specific orientation due to its anisotropy. YFeO 3 crystals display superior performance in the application magneto-optical current sensors and fast latching optical switches.