Spin-degree manipulation for one-dimensional room-temperature ferromagnetism in a haldane system.

The intricate correlation between lattice geometry, topological behavior and charge degrees of freedom plays a key role in determining the physical and chemical properties of a quantum-magnetic system. Herein, we investigate the introduction of the unusual oxidation state as an alternative pathway to modulate the magnetic ground state in the well-known = 1 Haldane system nickelate YBaNiO (YBNO). YBNO is topologically reduced to incorporate d-Ni ( = 1/2) in the one-dimensional Haldane chain system.

Calibration of local chemical pressure by optical probe.

Chemical stabilization of a high-pressure metastable state is a major challenge for the development of advanced materials. Although chemical pressure () can effectively simulate the effect of physical pressure (), experimental calibration of the pressure passed to local structural motifs, denoted as local chemical pressure () which significantly governs the function of solid materials, remains absent due to the challenge of probing techniques. Here we establish an innovative methodology to experimentally calibrate the and build a bridge between and via an optical probe strategy.

Reversible Structural Transformation between Polar Polymorphs of LiGeTeO.

LiGeTeO prepared at ambient pressure adopts the corundum derivative ordered ilmenite structure (rhombohedral R3). When heated at 1073 K and 3-5 GPa, the as-made LiGeTeO can convert into a LiSbO-derived LiTiTeO-type phase (orthorhombic Pnn2), which is the third LiSbO-derived double ABB'O phase in addition to LiTiTeO and LiSnTeO. This Pnn2 LiGeTeO phase spontaneously reverts to the R3 phase if annealed up to 1023 K at ambient pressure.