Ultrafast cooling and heating scenarios for the laser-induced phase transition in CuO

Hellsvik, Johan; Mentink, Johan H.; Lorenzana, J.

doi:10.1103/physrevb.94.144435

Cited by 11 publications

(19 citation statements)

References 56 publications

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“…For small x, qualitatively similar results were obtained by a step-like reduction of exchange parameters. Although several aspects of existing experimental work [79] on laser-induced dynamics in CuO are not captured by the simulations shown here (see [40] for a detailed discussion), the results do suggest new opportunities to achieve ultrafast laser-induced cooling of magnets by optical perturbations of exchange, strongly contrasting the laser-induced heating commonly observed in metallic magnets [6].…”

Section: Cooling By Perturbation Of Exchangecontrasting

confidence: 62%

Manipulating magnetism by ultrafast control of the exchange interaction

Mentink

2017

J. Phys.: Condens. Matter

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In recent years, the optical control of exchange interactions has emerged as an exciting new direction in the study of the ultrafast optical control of magnetic order. Here we review recent theoretical works on antiferromagnetic systems, devoted to (i) simulating the ultrafast control of exchange interactions, (ii) modeling the strongly nonequilibrium response of the magnetic order and (iii) the relation with relevant experimental works developed in parallel. In addition to the excitation of spin precession, we discuss examples of rapid cooling and the control of ultrafast coherent longitudinal spin dynamics in response to femtosecond optically induced perturbations of exchange interactions. These elucidate the potential for exploiting the control of exchange interactions to find new scenarios for both faster and more energy-efficient manipulation of magnetism.

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Section: Cooling By Perturbation Of Exchangecontrasting

confidence: 62%

Manipulating magnetism by ultrafast control of the exchange interaction

Mentink

2017

J. Phys.: Condens. Matter

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“…In particular, E > k B T N , where T N is the Néel temperature. We also note that perturbations ∆J in classical spin systems at finite temperature give rise only to a rapid relax-vi ation, not coherent oscillations 29 . Moreover, the oscillations show a macroscopic well-defined phase, since the excitation is impulsive: therefore a macroscopic ensemble measurement can reveal them.…”

Section: Excitation Mechanismmentioning

confidence: 79%

Laser-driven quantum magnonics and terahertz dynamics of the order parameter in antiferromagnets

et al. 2019

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The impulsive generation of two-magnon modes in antiferromagnets by femtosecond optical pulses, so-called femto-nanomagnons, leads to coherent longitudinal oscillations of the antiferromagnetic order parameter that cannot be described by a thermodynamic Landau-Lifshitz approach. We argue that this dynamics is triggered as a result of a laser-induced modification of the exchange interaction. In order to describe the oscillations we have formulated a quantum mechanical description in terms of magnon pair operators and coherent states. Such an approach allowed us to derive an effective macroscopic equation of motion for the temporal evolution of the antiferromagnetic order parameter. An implication of the latter is that the photo-induced spin dynamics represents a macroscopic entanglement of pairs of magnons with femtosecond period and nanometer wavelength. By performing magneto-optical pump-probe experiments with 10 femtosecond resolution in the cubic KNiF 3 and the uniaxial K 2 NiF 4 collinear Heisenberg antiferromagnets, we observed coherent oscillations at the frequency of 22 THz and 16 THz, respectively. The detected frequencies as a function of the temperature fit the two-magnon excitation up to the Néel point. The experimental signals are described as dynamics of magnetic linear dichroism due to longitudinal oscillations of the antiferromagnetic vector.

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“…4A ). This perturbation modulates the superexchange ( 32 ) of adjacent a-Fe 3+ and d-Fe 3+ spins and the associated coupling constant J ad by ( 16 , 33 , 34 )

We now put this model to test by conducting calculations of both dynamic and equilibrium states and by their comparison to our experimental observations on the ultrafast (τ fast ; Fig. 2B ) and the slower time scale (τ slow ; Fig.…”

Section: Resultsmentioning

confidence: 99%