X-ray Absorption Study of Structural Coupling in Photomagnetic Prussian Blue Analogue Core@Shell Particles

Abstract

X-ray absorption spectroscopy experiments of core@shell, photomagnetic, and Prussian Blue analogue heterostructures obtain the local structure around the magnetic transition-metal ions before and after illumination. Two samples, containing nickel hexacyanochromate (Ni−Cr) and cobalt hexacyanoferrate (Co−Fe) in Ni−Cr@Co−Fe and Co−Fe@ Ni−Cr geometries, were studied. Both materials display the wellknown photoinduced valence tautomerism for Co−Fe, accompanied by a large change in cobalt to nitrogen distances. Furthermore, these experimental results show a structural coupling of the photoactive Co−Fe layer to the passive Ni−Cr layer. Finally, the strain across the heterostructured interface in Co−Fe and Ni−Cr containing core@shell models is investigated with simulations that use custom potentials derived from density functional theory calculations.

Effects of an external magnetic field on a mixed spin-3/2 and spin-5/2 Ising ferrimagnet: A Monte Carlo study

“…As examples, we can mention the so‐called Prussian blue analogs, two‐dimensional lattices of mixed metal materials as [P(phenyl)[MnCr(oxalate)], superlattices of FeO or MnO, etc. . The production of magnetic materials by design is now possible.…”

Pressure-tuning of the photomagnetic response of heterostructured CoFe@CrCr-PBA core@shell nanoparticles

“…At 5 K, irradiation generates the light state, and a large number of metastable Fe 3+ (LS , S = 1/2)− CN −Co 2+ (HS , S = 3/2) pairs are generated and persist after the light is extinguished. The photo-CTIST establishs the PIM state in the CoFe-PBA core, and the thermal-CTIST strain, which formed while cooling, is relaxed as many of the CoFe pairs assume lattice dimensions close to those of the room temperature state [12]. The magnetic domains in the CrCr-PBA shells now experience a different magneto-crystalline anisotropy as long as the applied magnetic field is below nominally a few kG [18,40].…”

“…Using PBA heterostructures, a series of comprehensive studies by several groups have elucidated the robust magnetomechanical coupling at the interface of the two components and the interplay between the size of the cores and the thicknesses of the shells for observing photoinduced changes in the magnetic response [11][12][13][14]. Although the effect of external pressure on the magnetic behavior of several PBAs has been reported, including CoFe-PBA [15][16][17][18] and CrCr-PBA [19] that are the components of the system used in present study, the magnetic changes induced by light and pressure have not been previously reported for PBA heterostructures.…”

Magnetoelastic modeling of core-shell spin-crossover nanocomposites

“…Till now, the interest in the finite size effects properties [24][25][26][27] and in the manipulation [28], the design, and visualization [29] of small objects at the nanoscale is rapidly growing since the adapted near-field technologies are now available. This was the case, for example, of prussian blue analogs for which core-shell nanoparticles have been synthesized, and their thermal and photostriction properties have been investigated as a function of the thickness and the nature of the core and the shell [30][31][32][33][34].…”