Kwang-Yong Choi

Strong Anisotropy of Superexchange in the Copper-Oxygen Chains of La14xCaxCu24O41

Electron spin resonance data of Cu2+ ions in La(14)-xCaxCu24O41 single crystals (x = 9,11,12) reveal a very large width of the resonance line in the paramagnetic state. This signals an unusually strong anisotropy of approximately 10% of the isotropic Heisenberg superexchange in the Cu-O chains of this compound. The strong anisotropy can be explained by the specific geometry of two symmetrical 90 degrees Cu-O-Cu bonds, which boosts the importance of orbital degrees of freedom. Our data show the apparent limitations of the applicability of an isotropic Heisenberg model to the low-dimensional cuprates.

Existence of orbital polarons in ferromagnetic insulating La 1 − x Sr x Mn O 3 ( 0.11 ⩽ x ⩽ 0.14 ) revealed by giant phonon softening

We present an inelastic light scattering study of single crystalline (La

Raman spectroscopic signature of fractionalized excitations in the harmonic-honeycomb iridates β- and γ-Li2IrO3.

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Orbiton-mediated multiphonon scattering in La 1 − x Sr x Mn O 3

Pr

Spin–orbit coupled molecular quantum magnetism realized in inorganic solid

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Magnetic excitations and phonons in the spin-chain compound Na Cu 2 O 2

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Coupled spin-lattice fluctuations in a compound with orbital degrees of freedom: the Cr based dimer system Sr3Cr2O8

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Lattice and orbital fluctuations in TiPO4

Sr

Low-temperature mixed spin state of Co3+ in LaCoO3 evidenced from Jahn–Teller lattice distortions

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Anomalous frequency and intensity scaling of collective and local modes in a coupled-spin tetrahedral system Cu2Te2O5Cl2

MnO