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- Boya, K., et al.
(författare)
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Possible candidate for the realization of the floating phase in the S=5/2 frustrated spin-chain model : K3Fe(MoO4)2(Mo2O7 )
- 2024
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 109:15
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Tidskriftsartikel (refereegranskat)abstract
- The frustrated spin-chain (FSC) systems exhibit exotic ground states and distinct quantum phase transitions. The ?=1/2 FSC is known to exhibit the Kosterlitz-Thouless transition from a commensurate gapless phase to a fully dimerized gapped phase upon the ratio of next-nearest-neighbor to nearest-neighbor coupling (?=?2/?1) being tuned. On the other hand, the ?=5/2 FSC system is known to show transitions from a commensurate gapless phase to partially dimerized and incommensurate floating phases [Chepiga, Affleck, and Mila, Phys. Rev. B 105, 174402 (2022)]. While a large region of the floating phase has been theoretically predicted for the ?=5/2 FSC model when ?>0.43, it is yet to be explored experimentally. Here, we have investigated a compound K3Fe(MoO4)2(Mo2O7), having well-separated ?=5/2 FSCs. The electronic structure calculations show that the ?=?2/?1 is close to 0.9, being similar to another FSC compound Bi3FeMo2O12 (?≈1.1). No magnetic long-range order is found down to 0.09 K, despite the relatively sizable Curie-Weiss temperature ???=−18K. The magnetic heat capacity shows the power-law behavior, indicating that the compound exhibits gapless excitations. Based on the experimental results and the theoretical calculations employed by density functional theory, we argue that the titled system is a possible candidate for exhibiting the floating phase.
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| 2. |
- Guha, Pritam, et al.
(författare)
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Dendrimer Induced Bilayer Disintegration of Hybrid Vesicles
- 2024
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Ingår i: Journal of Oleo Science. - : Japan Oil Chemists' Society. - 1345-8957 .- 1347-3352. ; 73:4, s. 547-562
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Tidskriftsartikel (refereegranskat)abstract
- Physicochemical investigations on the inclusion of anionic polyamidoaminesuccinamic acid dendrimer, generation 5 (PAMAM-SA, G5) with positively charged hybrid vesicles (HCV), prepared using soylecithin, ion pair amphiphile (IPA), cholesterol and dihexadecyldimethylammonium bromide, were investigated by dynamic light scattering, transmission electron/atomic force microscopy (TEM/AFM), differential scanning calorimetry, fluorescence spectroscopy and surface pressure-time isotherm studies. Adsorption of dendrimer onto vesicle surface and subsequent bilayer disruption strongly depends on the bilayer composition and dendrimer concentration. Change in the zeta potential value with increasing dendrimer concentration suggests the dendrimer-vesicle interaction to be electrostatic in nature. AFM studies also confirm the adsorption of dendrimer as well as hole formation in the bilayer. Impact of the inclusion of dendrimer into the bilayer were further investigated through differential scanning calorimetry by monitoring the chain melting temperature and enthalpy of the chain melting processes. Dendrimer at low concentration does not alter bilayer integrity, while hole formations are noted at higher dendrimer concentration. Fluorescence anisotropy studies confirm the adsorption and subsequent bilayer disruption due to dendrimer inclusion. Dendrimer induced vesicle disintegration kinetics conclusively illustrate the transformation of cationic bilayer to monolayer and thereby exposing the role of IPA. In vitro cytotoxicity studies on PAMAM-SA, G5 and HCVs mixtures against human breast cancer cell line suggest that dendrimer-liposome aggregates (dendriosomes) exhibit substantial anticancer activities with insignificant side effects. It is expected that the dendriosomes may have application to host and deliver anticancer drug in the field of targeted drug delivery.
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