Photoinduced transitions in magnetoresistive manganites: A comprehensive view

Abstract

We use femtosecond x-ray diffraction to study the structural response of charge and orbitally ordered Pr 1−x Ca x MnO 3 thin films across a phase transition induced by 800 nm laser pulses. By investigating the dynamics of both superlattice reflections and regular Bragg peaks, we disentangle the different structural contributions and analyze their relevant time-scales. The dynamics of the structural and charge order response are qualitatively different when excited above and below a critical fluence f c . For excitations below f c the charge order and the superlattice is only partially suppressed and the ground state recovers within a few tens of nanosecond via diffusive cooling.When exciting above the critical fluence the superlattice vanishes within approximately half a picosecond followed by a change of the unit cell parameters on a 10 picoseconds time-scale. At this point all memory from the symmetry breaking is lost and the recovery time increases by many order of magnitudes due to the first order character of the structural phase transition. arXiv:1710.10085v1 [cond-mat.str-el] photoinduced metal-like phase of monoclinic VO 2 revealed by ultrafast electron diffraction," Science 346, 445-448 (2014). , "Light-induced superconductivity in a stripeordered cuprate," science 331, 189-191 (2011). 6 R Mankowsky, A Subedi, M Först, SO Mariager, M Chollet, HT Lemke, JS Robinson, JM Glownia, MP Minitti, A Frano, et al., "Nonlinear lattice dynamics as a basis for enhanced superconductivity in YBa 2 Cu 3 O 6.5 ," Nature (London) 516, 71-73 (2014).

Decoupling spin-orbital correlations in a layered manganite amidst ultrafast hybridized charge-transfer band excitation

“…2b). While a NIR pump can also excite free carriers in the system, the linear fluence dependence below the saturation threshold supports the notion that the pump induced reflectivity change at 1.55 eV must mainly come from the above-the-band-gap electronic excitations [11,14,29,33]. This is supported by the strongly gapped optical mode (Fig.…”

Correlations between electronic order and structural distortions and their ultrafast dynamics in the single-layer manganite Pr0.5Ca1.5MnPorer1, Rettig2, Bothschafter3 et al. 2020Phys. Rev. BSelf Cite7241View full textAdd to dashboardCite

“…The deviation of the model to the highest-fluence data is likely due to the remaining weakly excited regions of the probed volume due to an uncertainty in the determination of the pump and probe depths, particularly for bulk crystals. In addition, the high fluence data are further affected by an incomplete recovery between successive pump pulses, as was recently observed for 3D PCMO [23]: For fluences higher than required to fully melt the CO/OO order at the surface, the diffraction intensity no longer completely recovers between successive pump pulses due to the first-order character of the CO/OO transition, which results in slow dynamics of domain growth. The highest fluence time trace where this effect is largest was thus not included in the fitting procedure.…”

“…The ultrafast dynamics of electronic and magnetic phase transitions in manganites have been extensively studied [12][13][14][15][16][17][18][19]. In particular, resolving the structural dynamics in three-dimensional (3D) manganites following the photoinduced melting of the charge and orbital ordered (CO/OO) phase has been addressed in detail [11,[20][21][22][23][24]. It has been shown that a single order parameter that depends only on the electronic excitation is sufficient to describe the photoinduced ultrafast phase transition of the entire system, including charge and structural degrees of freedom [11].…”

“…The excitation suppresses the electronic order instantly [11,25] and the response of both the underlying antiferromagnetic order [14] and the JTD [11] occurs on the same timescale of about 100 fs. The atomic rearrangement of the heavy ions within the unit cell is completed within 1 ps, and the lattice constants readjust within 10-20 ps [23].…”

Evolution of the magnetic and polaronic order of $\rm{Pr_{1/2}Ca_{1/2}MnO_3}$ following an ultrashort light pulse

“…In the present study, the scale factors g x , g y and g z are dynamical variables, which describe long-wave length acoustic modes that are responsible for the strain effects in manganites [23,24]. We enforce g x = g y .…”