نتایج جستجو برای: adiabatic demagnetization
تعداد نتایج: 13693 فیلتر نتایج به سال:
Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR ...
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*Correspondence: Christopher H. Marrows, School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK e-mail: [email protected] We have studied experimentally the states formed in artificial square ice nanomagnet systems following demagnetization in a rotating in-plane applied magnetic field that reduces to zero in a manner that is linear in time. The final states are found to ...
Rare earth permanent magnet models are commonly used in the design of undulators and wigglers. Normally the operating point of the magnet in the B vs. H diagram corresponds to a linear reversible characteristic. The region of linearity is strongly dependent on the temperature. The operation of part of the magnet blocks in the region of non-linearity is responsible for the so-called irreversible...
We use single-cycle THz fields and the femtosecond magneto-optical Kerr effect to, respectively, excite and probe the magnetization dynamics in two thin-film ferromagnets with different lattice structures: crystalline Fe and amorphous CoFeB. We observe Landau-Lifshitz-torque magnetization dynamics of comparable magnitude in both systems, but only the amorphous sample shows ultrafast demagnetiza...
Ultrafast demagnetization has been studied in Si/Pts160 Åd / fCo25Ni75sxd /Pts8 Ådg20 sx=3, 4.5, and 6 Åd multilayers with perpendicular anisotropy by magneto-optical pump-probe measurements in the polar geometry. Time-resolved measurements made in the saturated state showed that maximum demagnetization was achieved within 300 fs. Hysteresis loops were measured at a time delay of 1.3 ps for tem...
A loss in smoothness of a switching process decreases the accuracy of an adiabatic invariant. Here we show that for classical Hamiltonian systems the degree of smoothness can be observed in the signal.
It has long been known that ferromagnets undergo a phase transition from ferromagnetic to paramagnetic at the Curie temperature, associated with critical phenomena such as a divergence in the heat capacity. A ferromagnet can also be transiently demagnetized by heating it with an ultrafast laser pulse. However, to date, the connection between out-of-equilibrium and equilibrium phase transitions,...
ethyl benzene used increasingly each year is the raw material of producing styrene monomer. this substanceis produced from benzene alkylation with ethylene or ethanol, depending on the availability and cost of rawmaterials. in this study benzene alkylation in the presence of ethanol in a catalytic fixed bed reactor inthree states of isotherm, adiabatic and non-isotherm-non-adiabatic is mathemat...
Ultrafast laser-induced demagnetization of Gd(0001) has been investigated by magneto-induced optical second harmonic generation and the magneto-optical Kerr effect which facilitate a comparison of surface and bulk dynamics. We observe pronounced differences in the transient changes of the surface and bulk sensitive magneto-optical signals which we attribute to transfer of optically excited, spi...
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