0000000001311790
AUTHOR
Miguel Castro
showing 9 related works from this author
Unprecedented multi-stable spin crossover molecular material with two thermal memory channels.
2013
et al.
Apertureless scanning near-field optical microscopy: a comparison between homodyne and heterodyne approaches
2006
International audience; In coherent homodyne apertureless scanning near-field optical microscopy (ASNOM) the background field cannot be fully suppressed because of the interference between the different collected fields, making the images difficult to interpret. We show that implementing the heterodyne version of ASNOM allows one to overcome this issue. We present a comparison between homodyne and heterodyne ASNOM through near-field analysis of gold nanowells, integrated waveguides, and a single evanescent wave generated by total internal reflection. The heterodyne approach allows for the control of the interferometric effect with the background light. In particular, the undesirable backgro…
A Switchable Molecular Rotator: Neutron Spectroscopy Study on a Polymeric Spin-Crossover Compound
2012
A quasielastic neutron scattering and solid-state 2H NMR spectroscopy study of the polymeric spin-crossover compound {Fe(pyrazine)[Pt(CN) 4]} shows that the switching of the rotation of a molecular fragment-the pyrazine ligand-occurs in association with the change of spin state. The rotation switching was examined on a wide time scale (10 -13-10 -3 s) by both techniques, which clearly demonstrated the combination between molecular rotation and spin-crossover transition under external stimuli (temperature and chemical). The pyrazine rings are seen to perform a 4-fold jump motion about the coordinating nitrogen axis in the high-spin state. In the low-spin state, however, the motion is suppres…
Spontaneous Magnetization in Ni−Al and Ni−Fe Layered Double Hydroxides
2008
Layered double hydroxides containing paramagnetic Ni (II) and diamagnetic/paramagnetic Al (III)/Fe (III) ions have been prepared and characterized. Ni 2Al(OH) 6(NO 3). nH 2O ( 1), Ni 2Fe(OH) 6(NO 3). nH 2O ( 2), Ni 2Fe(OH) 6(C 6H 8O 4) 0.5. nH 2O ( 3), and Ni 2Fe(OH) 6(C 10H 16O 4) 0.5. nH 2O ( 4) were prepared by coprecipitation at controlled pH as polycrystalline materials with the typical brucite-like structure, with alternating layers of hydroxide and the corresponding anions, which determine the interlayer separation. Magnetic studies show the appearance of spontaneous magnetization between 2 and 15 K for these compounds. Interestingly, the onset temperature for spontaneous magnetizati…
Spin-crossover in the [Fe(abpt)2(NCX)2] (X=S, Se) system: Structural, Magnetic, calorimetric and photomagnetic studies
1999
[EN] The compounds [Fe(abpt)(2)(NCS)(2)] (1) and [Fe(abpt)(2)(NCSe)(2)] (2) with abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole have been synthesized. The X-ray structures have been determined at 293 K. 1 and 2 are isostructural and crystallize in the monoclinic space group P2(1)/n with Z = 2, a = 8.538(8), b = 10.246(8), c = 16.45(2) Angstrom, beta = 93.98(9)degrees for 1 and a = 8.623(2), b = 10.243(3), c = 16.585(3) Angstrom, beta = 93.19(2)degrees for 2. In both complexes, the coordination core has a similar pseudo-octahedral geometry with the NCS- (1) and NCSe- (2) groups in the trans-position. Variable-temperature magnetic susceptibility data give evidence for a low-spin (LS)high…
Pulsed-laser switching in the bistability domain of a cooperative spin crossover compound: a critical study through calorimetry
2015
The photoswitching from the low spin (LS) to high spin (HS) state and the reverse process in the bistability domain of spin crossover (SCO) compounds is a promising function to be used in molecular electronic devices, and evidenced mainly through spectroscopy. The phenomenon, and in particular its mechanism, is however still under debate since some controversial experimental results have been reported. Here we present a calorimetric experimental study of the photoswitching of the [Fe(pyrazine)Pt(CN)4] SCO material by a nanosecond-pulsed green laser. Our results confirm that the single laser pulse of varying energies results in significant LS to HS transformations and show that calorimetry p…
CCDC 915257: Experimental Crystal Structure Determination
2013
Related Article: Maksym Seredyuk, M. Carmen Munoz, Miguel Castro, Tania Romero-Morcillo, Ana B. Gaspar,Jose Antonio Real|2013|Chem.-Eur.J.|19|6591|doi:10.1002/chem.201300394
CCDC 915259: Experimental Crystal Structure Determination
2013
Related Article: Maksym Seredyuk, M. Carmen Munoz, Miguel Castro, Tania Romero-Morcillo, Ana B. Gaspar,Jose Antonio Real|2013|Chem.-Eur.J.|19|6591|doi:10.1002/chem.201300394
CCDC 915258: Experimental Crystal Structure Determination
2013
Related Article: Maksym Seredyuk, M. Carmen Munoz, Miguel Castro, Tania Romero-Morcillo, Ana B. Gaspar,Jose Antonio Real|2013|Chem.-Eur.J.|19|6591|doi:10.1002/chem.201300394