Tailoring Gilbert damping of metallic ferromagnetic thin films is one of the central interests in spintronics applications. Here we report a giant Gilbert damping anisotropy in epitaxial Co50Fe50 thin film with a maximum-minimum damping ratio of 400 %, determined by broadband spin-torque as well as inductive ferromagnetic resonance. We conclude that the origin of this damping anisotropy is the variation of the spin orbit coupling for different magnetization orientations in the cubic lattice, which is further corroborate from the magnitude of the anisotropic magnetoresistance in Co50Fe50.In magnetization dynamics the energy relaxation rate is quantified by the phenomenological Gilbert damping in the Landau-Lifshits-Gilbert equation [1], which is a key parameter for emerging spintronics applications [2][3][4][5][6]. Being able to design and control the Gilbert damping on demand is crucial for versatile spintronic device engineering and optimization. For example, lower damping enables more energy-efficient excitations, while larger damping allows faster relaxation to equilibrium and more favorable latency. Nevertheless, despite abundant approaches including interfacial damping enhancement [7-9], size effect [10,11] and materials engineering [12][13][14], there hasn't been much progress on how to manipulate damping within the same magnetic device. The only well-studied damping manipulation is by spin torque [15][16][17][18], which can even fully compensate the intrinsic damping [19,20]. However the requirement of large current density narrows its applied potential.An alternative approach is to explore the intrinsic Gilbert damping anisotropy associated with the crystalline symmetry, where the damping can be continuously tuned via rotating the magnetization orientation. Although there are many theoretical predictions [21][22][23][24][25], most early studies of damping anisotropy are disguised by two-magnon scattering and linewidth broadening due to field-magnetization misalignment [26][27][28][29]. In addition, those reported effects are usually too weak to be considered in practical applications [30,31].In this work, we show that a metallic ferromagnet can exhibit a giant Gilbert damping variation by a factor of four along with low minimum damping. We investigated epitaxial cobalt-iron alloys, which have demonstrated new potentials in spintronics due to their ultralow dampings [32,33]. Using spin-torque-driven and inductive ferromagnetic resonance (FMR), we obtain a fourfold (cubic) damping anisotropy of 400% in Co 50 Fe 50 thin films between their easy and hard axes. For each angle, the full-range frequency dependence of FMR linewidths can be well reproduced by a single damping parameter α. Furthermore, from first-principle calculations and temperature-dependent measurements, we argue that this giant damping anisotropy in Co 50 Fe 50 is due to the variation of the spin-orbit coupling (SOC) in the cubic lattice, which differs from the anisotropic density of state found in ultrathin Fe film [30]. We support our conclu...

Rare ruthenium(II) complexes bearing a pyridylbased pyrazolyl-imidazolyl ligand were synthesized and exhibited exceptionally high catalytic actiVity in the transfer hydrogenation of ketones in 2-propanol at 82 °C or room temperature, reaching 100% conVersion of the substrates and final TOFs up to 7.2 × 10 5 h -1 with 0.05 mol % catalyst at 82 °C and 55 800 h -1 with 0.1 mol % catalyst at room temperature.

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Palladium-catalyzed oxidative annulation of ortho-alkenylanilines and allenes to constitute valuable, but synthetically challenging, benzo[b]azepines has been developed. The procedure, involving the cleavage of the terminal C(sp)-H bond of the vinyl moiety and the participation of allenes as two-carbon cycloaddition partner, is attractive in terms of assembly efficiency and environmental friendliness. The transformation features mild reaction conditions and good functional group tolerance, resulting in a variety of benzo[b]azepines in good to excellent yields.

Palladium-catalyzed oxidative cyclocarbonylation of 2-vinylphenols constitutes a simple, direct method for the synthesis of coumarins. The reaction conditions, employing low pressures of CO, and air or 1,4- benzoquinone as the oxidant, are attractive in terms of environmental considerations and operational simplicity. Coumarins with a variety of functional groups were prepared in yields up to 85%.

A family of hemilabile ruthenium(II) NNN complexes bearing a unsymmetrical 2-(benzoimidazol-2-yl)-6-(pyrazol-1-yl)pyridine ligand has been synthesized and exhibited good to excellent catalytic activity in transfer hydrogenation of ketones in refluxing 2-propanol, reaching final TOFs up to 7.2 × 105 h−1 with 0.05 mol % loading. The γ-NH effect of the benzoimidazol-2-yl moiety in the ligand and coordination modes of the metal center in a Ru(II) NNN complex has great influence on the catalytic activity of the complex catalyst in transfer hydrogenation of ketones. It has been demonstrated that one of the structural prerequisites for an active Ru(II) complex catalyst is the coordinatively unsaturated environment around the metal center in the complex or the precatalyst, and the catalytic activity of a complex catalyst can be enhanced by making its metal center cationic. This paper presents a methodology to construct new types of efficient Ru(II) complex catalysts for transfer hydrogenation of ketones.

A highly efficient palladium-catalyzed domino process has been developed for the synthesis of quinazolino[3,2-a]quinazolinones by forming five new bonds in a single step. Despite the high density and variety of functional groups on the substrates, the tetracyclic quinazolinones were obtained in good to excellent yields.

Palladium complexes of two new types of unsymmetrical pyridyl-supported pyrazolyl-N-heterocyclic carbene ligands were synthesized and structurally characterized. A strategy to release the steric strain of the ligand was realized by the introduction of methylene linkers to the ligand molecule. All the palladium complexes exhibited good to excellent catalytic activity in Suzuki-Miyaura reactions of phenyl or p-tolylboronic acid with aryl halides including iodobenzene, aryl bromides, and activated aryl chlorides under mild conditions, revealing that the new ligands are promising for the construction of highly active transition-metal catalysts.