TY - GEN A1 - Miao, Hu A1 - Lorenzana, José A1 - Seibold, Götz A1 - Peng, Yingying A1 - Amorese, Andrea A1 - Yakhou-Harris, Flora A1 - Kummer, Kurt A1 - Brookes, Nicholas B. A1 - Konik, R. M. A1 - Thampy, Vivek A1 - Gu, G. D. A1 - Ghiringhelli, Giacomo Claudio A1 - Braicovich, Lucio A1 - Dean, M. P. M. T1 - High-temperature charge density wave correlations in La1.875Ba0.125CuO4 without spin–charge locking T2 - Proceedings of the National Academy of Sciences of the United States of America PNAS N2 - Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes of charge and spin, with a locked periodicity, others host charge density waves (CDWs) without any obviously related spin order. Here we use resonant inelastic X-ray scattering to follow the evolution of charge correlations in the canonical stripe-ordered cuprate La1.875Ba0.125CuO4 across its ordering transition. We find that high-temperature charge correlations are unlocked from the wavevector of the spin correlations, signaling analogies to CDW phases in various other cuprates. This indicates that stripe order at low temperatures is stabilized by the coupling of otherwise independent charge and spin density waves, with important implications for the relation between charge and spin correlations in the cuprates. KW - charge density waves KW - stripes KW - high-temperature superconductivity KW - cuprates KW - X-rays Y1 - 2017 UR - http://www.pnas.org/content/early/2017/10/31/1708549114.abstract U6 - https://doi.org/10.1073/pnas.1708549114 SN - 1091-6490 SN - 0027-8424 VL - 114 IS - 47 SP - 12430 EP - 12435 ER - TY - GEN A1 - Miao, Hu A1 - Fumagalli, Roberto A1 - Rossi, M. A1 - Lorenzana, José A1 - Seibold, Götz A1 - Yakhou-Harris, Flora A1 - Kummer, K. A1 - Brookes, Nicholas B. A1 - Gu, G. D. A1 - Braicovich, Lucio A1 - Ghiringhelli, Giacomo Claudio A1 - Dean, M. P. M. T1 - Formation of Incommensurate Charge Density Waves in Cuprates T2 - Physical Review X N2 - Although charge density waves (CDWs) are omnipresent in cuprate high-temperature superconductors, they occur at significantly different wave vectors, confounding efforts to understand their formation mechanism. Here, we use resonant inelastic x-ray scattering to investigate the doping- and temperature-dependent CDW evolution in La₂₋ₓBaₓCuO₄ (x=0.115–0.155). We discover that the CDW develops in two stages with decreasing temperature. A precursor CDW with a quasicommensurate wave vector emerges first at high temperature. This doping-independent precursor CDW correlation originates from the CDW phase mode coupled with a phonon and “seeds” the low-temperature CDW with a strongly doping-dependent wave vector. Our observation reveals the precursor CDW and its phase mode as the building blocks of the highly intertwined electronic ground state in the cuprates. KW - Research Areas Charge density waves KW - Electrical Properties KW - Cuprates KW - Strongly correlated systems KW - Resonant inelastic x-ray scattering KW - Superconductivity Y1 - 2019 UR - https://journals.aps.org/prx/abstract/10.1103/PhysRevX.9.031042 U6 - https://doi.org/10.1103/PhysRevX.9.031042 SN - 2160-3308 VL - 9 IS - 3 SP - 031042-1 EP - 031042-11 ER - TY - JOUR A1 - Fong, Mun‐Oon A1 - Chen, Xiangping A1 - Wong, Jie‐Wei A1 - Lok, Tow‐Jie A1 - Li, Siyang A1 - Low, Jia Tee A1 - Nordin, Nur Syahirra A1 - Miao, Zhikun A1 - Hu, Qiannan A1 - Neffe, Axel T. A1 - Wong, Tuck‐Whye A1 - Li, Tiefeng A1 - Yang, Wei T1 - Multifunctional Roles of Iron Oxide Nanoparticles in a Reversible Shape‐Memory Composite JF - Advanced Functional Materials N2 - The utilization of functional fillers in the development of composite materials has come a long way since its advent to improve physical, chemical, or mechanical properties of the base material. However, the heterogenous roles contributed by a single type of filler remain uncommon in this field. Here the endowment of various modifications to a 1,8‐octanediol/1,12‐dodecanedioic acid/citric acid (OD/DDA/CA) matrix through the incorporation of iron oxide nanoparticles (IONPs) is reported. Owing to the relaxation and hysteresis loss behaviors of IONPs when exposed to an alternating magnetic field (AMF), the composites demonstrate a magnetothermal response. Similarly, the excitation and relaxation of electrons in IONPs under near‐infrared light (NIR) enable photothermic‐responsiveness. In combination, two findings nurtured an observed shape‐memory effect when the samples are under actuation by these indirect stimuli, where a shape recovery ratio (≥98%) and reversible strain (≤7%) are recorded. Moreover, the catalytic role of IONPs aided transesterification in the covalent network, demonstrated by successful repeated cycles of shape reconfiguration of the samples. This work highlights the prospectives of multifunctional composite fillers in the exploration of bio‐derived composite smart materials. KW - Shape-Memory Polymer KW - Composite KW - Iron Oxide Nanoparticle KW - bio-based Y1 - 2024 U6 - https://doi.org/10.1002/adfm.202418409 SN - 1616-301X PB - Wiley ER -