Dynamic response of the spin-crossover solid Co(H-2(fsa)(2)en)(py)(2) to a pulsed magnetic field

Article

关键词: TRANSITION;    MODEL;    COMPLEXES;    LIGHT;   

DOI  :  10.1103/PhysRevB.65.172412

来源: SCIE

【 摘 要 】

The spin transition between the paramagnetic high-spin (HS) and low-spin (LS) electronic states of Co-II(H-2(fsa)(2)en)(py)(2), [H-2(fsa)(2)en=N,N-'-ethylene bis(3-carboxysalicylaldimine), py=pyridine] under a pulsed and intense magnetic field (32 T) has been probed by optical reflectivity. In the absence of perturbation, a thermal hysteresis loop (DeltaT=19.4 K,T-1/2=126 K) was detected. Applying a magnetic field of 32 T to the solid, the initial state of which belongs to the ascending branch of the hysteresis loop, leads to an irreversible and quasicomplete S=1/2-->S=3/2 transition. The experimental evidence of this crossover triggered by a pulsed magnetic field is reported here in conjunction with an adequate Ising-like model. This two-level model, used as a first approach, allows us to reproduce quantitatively the -4.9 K shift in transition temperature under the effect of the 32 T static magnetic field. The dynamic aspects of the previous model are also explored, leading to a description of the main features of the phenomenon. Indeed, an irreversible (reversible) jump of the high-spin fraction is predicted when the pulsed magnetic field is applied in the metastable LS (HS) phase.

【 授权许可】

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