Manipulating magnons via ultrafast magnetization modulation

Unifying ultrafast magnetization dynamics.

We present a microscopic model that successfully explains the ultrafast equilibration of magnetic order in ferromagnetic metals at a time scale tau(M) of only a few hundred femtoseconds after pulsed laser excitation. It is found that tau(M) can be directly related to the so-called Gilbert damping factor sigma that describes damping of GHz precessional motion of the magnetization vector. Indepen...

Detection of coherent magnons via ultrafast pump-probe reflectance spectroscopy in multiferroic Ba0.6Sr1.4Zn2Fe12O22.

We report the detection of a magnetic resonance mode in multiferroic Ba0.6Sr1.4Zn2Fe12O22 using time-domain pump-probe reflectance spectroscopy. Magnetic sublattice precession is coherently excited via picosecond thermal modification of the exchange energy. Importantly, this precession is recorded as a change in reflectance caused by the dynamic magnetoelectric effect. Thus, transient reflectan...

Ultrafast magnetization dynamics in ferromagnetic materials

In recent magneto optical experiments (TR-MOKE) the timescale of laser induced demagnetization was found to be shorter than 0.5 ps. However, doubts have been raised if the measured signal reflects genuine loss of magnetic moment at all. Also, for these experiments no broadly accepted theory exists. Although a few models are able to fit the data, they generally have in common that they violate o...

Ultrafast magnetization dynamics of spintronic nanostructures.

The ultrafast (sub-nanosecond) magnetization dynamics of ferromagnetic thin films and elements that find application in spintronic devices is reviewed. The major advances in the understanding of magnetization dynamics in the two decades since the discovery of giant magnetoresistance and the prediction of spin-transfer torque are discussed, along with the plethora of new experimental techniques ...

Minimum Field Strength in Ultrafast Magnetization Reversal