An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Mix and match: Topotactic hydride reduction allows the first synthesis of the fully reduced parent phase, Sr4Fe6O12, of the important family Sr4Fe6O13±δ. The structure provides a rare example of pairs of edge-linked tetrahedra, in this case containing a random arrangement of FeII and FeIII centers at 300 K. On cooling, charge order occurs so that each pair of tetrahedra has one FeII (white) and one FeIII (black) center. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
The n = 1 Ruddlesden–Popper (RP) phases LaSrM0.5Ru0.5O4±δ (M = Co, Ni and Zn) have been prepared by solid state reactions and structurally characterized by powder X-ray and electron diffraction. All the samples adopt the tetragonal I4/mmm space group with random M and Ru cation occupation on the B-sites. The potential causes of no cation ordering are discussed. A combined analysis of the tolerance factors, the distortion of the octahedral coordination of M and Ru cations and the magnetic interactions between M and Ru cations provide a better understanding for forming a phase with 3D cation ordering on the B-sites in the n = 1 RP phases. The investigation of XPS spectra suggests that the transition element species exist as mixed ion pairs, Ru(4−δ)+–Ru4+ ↔ Co2+–Co3+ in LaSrCo0.5Ru0.5O4, and Ru4+–Ru(4+δ)+ ↔ Ni+–Ni2+ in LaSrNi0.5Ru0.5O4, which is consistent with cation disorder over the B sites. LaSrCo0.5Ru0.5O4 shows a weakly ferromagnetic behaviour below 50 K; LaSrNi0.5Ru0.5O4 is evidenced by the presence of long-range magnetic ordering at a Néel temperature of 125 K, and LaSrZn0.5Ru0.5O4 exhibits a paramagnetic behaviour down to 5 K. Due to atomic disorder, Ru4d, O2p covalent coupling is weakened, strengthening the intraatomic spin–spin coupling among the π* electrons. Charge transfer between Ru and Co or Ru and Ni, as well as the increasing overlap of both nearest-neighbour and next-nearest-neighbour Ru 4d electrons due to atomic disorder, favour the formation of ferromagnetic interactions. Although antiferromagnetism is dominant, particularly in LaSrNi0.5Ru0.5O4, ferromagnetic interactions are stronger in the title compounds than in the related La2MRuO6 (M = Co, Ni) double perovskites where the B-site cations are ordered.
Abstract Organic photothermal materials have attracted extensive attention due to their designable molecular structure, tunable excited‐state properties, and excellent biocompatibility, however, the development of near‐infrared II (NIR‐II) absorbing organic photothermal materials with high photothermal conversion efficiency (PTCE) and molar extinction coefficient ( ɛ ) remains challenging. Herein, a novel “electron‐donor iteration” strategy is proposed to construct organic photothermal dendrimers (CR‐DPA‐T, CR‐(DPA) 2 ‐T and CR‐(DPA) 3 ‐T) with donor‐ π ‐acceptor‐ π ‐donor (D ‐π‐ A‐ π ‐D) features and diradical characteristics. Owing to the enhanced D–A effect and intramolecular motions, their absorption and photothermal capacity increase as the generation grows. Surprisingly, an excellent photothermal performance ( ɛ 1064 × PTCE 1064 ) with a superb value of 2.85 × 10 4 in the NIR‐II region is achieved for CR‐(DPA) 3 ‐T nanoparticles (CR‐(DPA) 3 ‐T NPs) compared to most reported counterparts. Besides, CR‐(DPA) 3 ‐T NPs exhibit superior antitumor efficacy by the synergistic effect of photothermal therapy (PTT) and immunotherapy, efficiently inhibiting the growth of both primary and distant tumors. To the best knowledge, organic photothermal dendrimer is for the first time reported, and a universal donor engineering strategy is offered to develop NIR‐II‐absorbing organic photothermal materials for photothermal immunotherapy.
Polycrystalline Sr2FeMoO6 compounds with most vacancies at normal Fe sites were fabricated through Mo hole doping; its effect is similar to Fe3+ by our estimation. Sharp increase of magnetoconductance at low field was evidence of spin-polarized tunneling between the grains. The room temperature low-field magnetoresistivity at optimal doping x=0.03 is 8.5% in 3000Oe and increases to 11.4% in 1T associated with soft magnetic behaviors; furthermore it exhibits a ferromagnetic Curie temperature of 450K, connected with hole doping effect. The improved magnetoresistivity behavior was related to Curie temperature.
The electrical, magnetic and transport properties of Zn doped polycrystalline samples of Sr2Fe1−xZnxMoO6 (x = 0,0.05,0.15 and 0.25) with the double perovskite structure have been investigated. The subtle replacement of Fe3+ ions by Zn2+ ions facilitates the formation of a more ordered structure, while further substitution leads to disordered structure because of the presence of a striped phase. Analysis of the x-ray powder diffraction patterns based on Rietveld analysis indicates that the replacement of Fe3+ by Zn2+ ions favours the formation of Mo6+ ions. The spin-glass behaviour can be explained on the basis of the competition between the antiferromagnetic superexchange and the ferromagnetic double-exchange interaction. The low-field magnetoresistance was moderately enhanced at x = 0.05, and its origin was found to be the competition between the decrease of the concentration of the itinerant electrons and the weaker antiferromagnetic superexchange in the antiphase boundaries. An almost linear negative magnetoresistance in moderate field has been observed for x = 0.25. A possible double-exchange mechanism is proposed for elucidating the observations; it also suggests a coexistence of (Fe3+,Mo5+) and (Zn2+,Mo6+) valence pairs.
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