Double-decker phthalocyanine complexes with Tb3+ or Dy3+ showed slow magnetization relaxation as a single-molecular property. The temperature ranges in which the behavior was observed were far higher than that of transition-metal-cluster single-molecule magnets (SMMs). significant rise results from mechanism process different SMMs. effective energy barrier for reversal magnetic moment is determined by ligand field around lanthanide ion, gives lowest degenerate substate large |Jz| value and...

Optical spectra and their temperature dependence have been investigated for a prototypical double-exchange ferromagnet ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ ( $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.175$). The optical conductivity spectrum above ${T}_{c}$ is characterized by interband transitions between the exchange-split bands gradually changes into intraband excitations with decrease of temperature, accompanied conspicuous transfer spectral...

Alternating current (ac) magnetic susceptibility and magnetization hysteresis loop measurements have been carried out for anionic bis(phthalocyaninato)terbium bis(phthalocyaninato)dysprosium. The two mononuclear lanthanide complexes show the characteristic temperature frequency dependence in ac signals, reflecting their slow relaxation. From Arrhenius analysis of data obtained a diluted sample diamagnetic matrix, it has found that relaxation Tb complex is dominated by two-phonon Orbach...

We report that the organic salt (EDO-TTF)2PF6 with 3/4-filled-band (1/4-filled in terms of holes), which forms an metal strong electron and lattice correlation, shows a highly sensitive response to photoexcitation. An ultrafast, photoinduced phase transition from insulator can be induced very weak excitation intensity at near room temperature. This makes material attractive for applications switching devices room-temperature operation. The observed photo-induced spectroscopic change this...

Optical conductivity spectra and their variation with temperature doping level x have been investigated for single crystals of ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sr}}_{\mathrm{x}}$${\mathrm{MnO}}_{3}$n(0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.3). For the low-doped insulating crystal (x=0.1) which shows a ferromagnetic state at low temperature, spectral weight optical increases only in inner-gap region around 0.5 eV, but no Drude part emerges due to carrier...

Two-electron oxidation of [{Pc(OEt)8}2TbIII]- [Pc(OEt)8=dianion 2,3,9,10,16,17,23,24-octaethoxyphthalocyanine], which leads to a longitudinal contraction the coordination space single-4f-ionic single-molecule magnet (SMM), resulted in significant increase magnetization-reversal barrier energy and remarkable upward temperature shift chi'' peaks chi'T drops. This is first evidence that dynamic magnetism 4f SMMs can be controlled by redox reaction on ligand side without introducing any...

An alternating-current (ac) magnetic susceptibility measurement for the [(Pc)2TbIII]0 complex (Pc = phthalocyaninato) has shown that ligand oxidation of anionic [(Pc)2TbIII]- gives rise to a significant upward shift temperature range where magnetization response shows phase lag behind time-varying external field. The peaks out-of-phase component ac π-radical were observed at 50, 43, and 36 K with fields 103, 102, 10 Hz, respectively, which more than higher corresponding values closed-shell...

Chemically induced longitudinal contraction of the square-antiprism coordination polyhedron a peripherically substituted bis(phthalocyaninato)dysprosiumate(III), dysprosium-based single-4f-ionic single-molecule magnet having J z = +/- (13)/ 2 Kramers doublet ground state, resulted in drastic changes dynamical magnetism including doubling energy barrier, 2-order-of-magnitude decrease spin reversal rate, significant rise blocking temperature, and first observation emergence large remanent...

Correlated electron systems can undergo ultrafast photoinduced phase transitions involving concerted transformations of electronic and lattice structure. Understanding these phenomena requires identifying the key structural modes that couple to states. We report photoresponse molecular crystal Me4P[Pt(dmit)2]2, which exhibits a charge transfer similar between thermally accessible states, demonstrate how femtosecond diffraction be applied directly observe associated motions. Even for such...

The temperature-dependent electronic structure has been investigated for a single crystal of magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4})$ by measurements the optical-conductivity spectrum. Upon charge-ordering (Verwey) transition ${(T}_{V}=121 \mathrm{K})$, clear opening optical gap (0.14 eV) is observed. Above ${T}_{V},$ conductivity spectra shows notable spectral weight transfer in $\mathrm{Fe} 3d$ intersite region $(0\ensuremath{-}2 \mathrm{eV})$, while preserving pseudogap or...

Optical spectra of a single crystal ${\mathrm{La}}_{1.67}$${\mathrm{Sr}}_{0.33}$${\mathrm{NiO}}_{4}$, which undergoes charge-ordering transition at ${\mathit{T}}_{\mathrm{CO}}$\ensuremath{\sim}240 K, have been investigated for wide ranges photon energy (0.008--3 eV) and temperature (10--480 K). The opening charge gap as well change the magnitude (2\ensuremath{\Delta}) with is clearly observed below ${\mathit{T}}_{\mathrm{CO}}$, an anomalously large ratio...

This work reviews the experimental studies on photo-induced cooperative phenomena (photo-induced phase transitions, PIPT), which are related to ultrafast structural and electronic-state dynamics. The review includes a brief history of this research field. current growth PIPT is facilitated by deep collaboration between quantum beam science materials science. Meanwhile, owing developments in technology, concept itself has largely expanded. In initial stage research, dynamical process was...

The change of the electronic and magnetic properties as well charge-ordering (CO) transition related with lattice dynamics has been systematically investigated for crystals ${R}_{1/3}{\mathrm{Sr}}_{2/3}{\mathrm{FeO}}_{3} (R=\mathrm{La},$ Pr, Nd, Sm, Gd) by transmission electron microscopy measurements transport, magnetic, optical properties. In ${R}_{1/3}{\mathrm{Sr}}_{2/3}{\mathrm{FeO}}_{3},$ hybridization O $2p$ Fe $3d$ states, or effective d hopping interaction, can be controlled to some...

Changes in electrical, magnetic, and optical properties have been investigated for the doping-induced insulator-metal (I-M) transition hole-doped Mott insulators, ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{VO}}_{3}$. In spectra, I-M is characterized by transfer of spectral weight into in-gap region. Resistivity metallic phase near critical magnetic boundary shows such a temperature dependence as expressed relation...

The quasistable state in the photoinduced phase transition for quasi-one-dimensional quarter-filled organic conductor $(\mathrm{EDO}\mathrm{\text{\ensuremath{-}}}\mathrm{TTF}{)}_{2}{\mathrm{PF}}_{6}$ has been examined by ultrafast reflective measurements and time-dependent model calculations incorporating both electron-electron electron-phonon interactions. transient optical conductivity spectrum over a wide probe photon-energy range revealed that photoexcitation induced new type of...

Alternating-current (ac) magnetic susceptibility measurements for tris(dipicolinato) complexes with a trivalent heavy lanthanide ion, [N(C2H5)4]3[Ln(dipic)(3)] x nH2O (dipic = pyridine-2,6-dicarboxylate; Ln Tb, Dy, Ho, Er, Tm, or Yb) are reported. While none of the six showed magnetization lag from ac field 10-10(3) Hz above 1.8 K, and Yb odd numbers 4f electrons exhibited in static field. This phenomenon is explained to be caused by elimination fast relaxation path, which only effective...

The photoisomerization of molecules is widely used to control the structure soft matter in both natural and synthetic systems. However, structural dynamics during isomerization their subsequent response are difficult elucidate due complex ultrafast nature. Herein, we describe formation higher-orientation liquid-crystalline (LC) azobenzene via linearly polarized ultraviolet light (UV) using time-resolved electron diffraction. orientation caused by trans-to-cis molecules. Our observations...

Photoinduced effects on the charge- and orbital-ordered (CO/OO) states in a layered perovskite manganite ${\mathrm{La}}_{0.5}{\mathrm{Sr}}_{1.5}{\mathrm{MnO}}_{4}$ have been investigated with femtosecond polarization-sensitive pump-probe spectroscopy. Disappearance of optical birefringence as well conspicuous change spectrum indicates immediate destruction CO/OO upon photoexcitation. A large difference temporal evolution reflectivity was observed, indicating that adiabatic, fast...

Femtosecond optical response was investigated on a perovskite-type cobalt oxide, Pr0.5Ca0.5CoO3 during an insulator-metal (I-M) transition accompanied with the change in spin configuration. After photoirradiation at 30 K, reflectivity showed sudden and large increase subsequent variation depending observed photon energy. An exact calculation of Maxwell's equations for after enabled us to observe ultrafast dynamics I-M phase motion photonically created metallic domain velocity ultrasonic wave.

Change of electronic and lattice structures upon the orbital charge-ordering (OO-CO) transition has been investigated for a single-layer manganite crystal ${\mathrm{La}}_{1/2}{\mathrm{Sr}}_{3/2}{\mathrm{MnO}}_{4}.$ The optical birefringence signal probes orbital-ordering-induced anisotropy in originally tetragonal ${\mathrm{MnO}}_{2}$ lattice. In course OO-CO transition, conductivity spectrum shows significant change over wide energy region (0--3 eV), forming prominent peak around 1.3 eV as...

The lattice and electronic response in the course of concomitant charge orbital-ordering transition has been investigated for single crystals layered manganites, single-layered ${\mathrm{La}}_{0.5}{\mathrm{Sr}}_{1.5}{\mathrm{MnO}}_{4},$ bilayered ${\mathrm{LaSr}}_{2}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7},$ by Raman-scattering spectroscopy. In charge-orbital-ordered state $(T<217$ K ${\mathrm{La}}_{0.5}{\mathrm{Sr}}_{1.5}{\mathrm{MnO}}_{4}$ $\ensuremath{\sim}100 \mathrm{K}<T<210$...

The change of the electronic structure and lattice dynamics upon charge-ordering (CO) transition has been investigated for a ${\mathrm{La}}_{1/3}{\mathrm{Sr}}_{2/3}{\mathrm{FeO}}_{3}$ crystal by measurements optical spectra. CO transition, as characterized sequential 2:1 ordering nominal ${\mathrm{Fe}}^{3+}$ ${\mathrm{Fe}}^{5+}{(111)}_{c}$ sheets at ${T}_{\mathrm{CO}}=198\mathrm{K},$ activates several additional phonon modes due to charge modulation opens an gap (up...

The atomic and electronic dynamics in the topological insulator (TI) Bi2Te3 under strong photoexcitation were characterized with time-resolved electron diffraction mid-infrared spectroscopy. Three-dimensional TIs as bulk insulators an conduction surface band have shown a variety of exotic responses terms transport when observed conditions applied pressure, magnetic field, or circularly polarized light. However, motions their correlation between systems not been explored. artificial transient...

Highly anisotropic optical conductivity spectra and their temperature variation have been investigated for a layered ferromagnetic ${(T}_{\mathrm{c}}$=121 K) crystal of La${}_{2\ensuremath{-}2x}$Sr${}_{1+2x}$Mn${}_{2}$O${}_{7}$ $(x$=0.4). The in-plane show conspicuous spectral-weight transfer over an energy region 0--3 eV with evolution spin polarization below ${T}_{\mathrm{c}}$ in the ferromagnetic, highly conducting ground state form prominent peak structure around 0.4 minimal Drude...