arXiv subjects

T. T. Gareev

Publications and source records attributed to T. T. Gareev.

3 recordsLinked to original sources

arXiv2026

Electrically-gated laser-induced spin dynamics in magneto-electric iron garnet at room temperature

Ultrafast pump-probe imaging reveals that the efficiency of optical excitation of coherent spins waves in epitaxial iron garnet films can be effectively controlled by an external electric field at room temperature. Although a femtosecond laser pulse alone does not excite any pronounced coherent spin oscillations, an electrical gating with the field of 0.5 MV/m dramatically changes the outcome in a laser-induced launching of spin waves. The effect, demonstrated under room-temperature conditions, is estimated to be orders of magnitude larger than in magnetic van der Waals semiconductors observed at 10 K. This electrical gating of laser-induced spin dynamics enriches opto-magnonics with a new tool and thus opens up a new avenue in fundamental and applied magnonics research.

physics.app-ph↗

arXiv2025

Strongly inhomogeneous spin dynamics induced by ultrashort laser pulses with a gradient intensity profile

The optical pump-probe technique is a common tool for investigation of ultrafast spin dynamics, which usually utilizes single-diode detection averaging the dynamics over the pumped area. Using ultrafast imaging technique, we show experimentally that a femtosecond laser pulse with a gradient distribution of intensity efficiently excites strongly inhomogeneous spin dynamics on spatial scales much smaller than the pump spot size. The mechanism responsible for the inhomogeneous distribution is based on temperature gradients and corresponds to a sign change of the torque derivative in different areas of the pump. We argue that the observed phenomenon is general for the systems with competitive magnetic anisotropies. Overlooking this effect in the majority of pump-probe experiments may result in a dramatic underestimation of the live time and amplitude of the laser-induced spin dynamics.

physics.app-ph↗

arXiv2023

Coherent THz Spin Dynamics in Antiferromagnets Beyond the Approximation of the Néel vector

Controlled generation of coherent spin waves with highest possible frequencies and the shortest possible wavelengths is a cornerstone of spintronics and magnonics. Here, using the Heisenberg antiferromagnet RbMF$_3$, we demonstrate that laser-induced THz spin dynamics corresponding to pairs of mutually coherent counter propagating spin waves with the wavevectors up to the edge of the Brillouin zone cannot be understood in terms of magnetization and antiferromagnetic (Néel) vectors, conventionally used to describe spin waves. Instead, we propose to model such spin dynamics using the spin correlation function. We derive a quantum-mechanical equation of motion for the latter and emphasize that, unlike the magnetization and antiferromagnetic vectors the spin correlations in antiferromagnets do not exhibit inertia.

cond-mat.str-el↗