Dynamics of Spin Crossover Molecular Complexes.

We review the current understanding of the time scale and mechanisms associated with the change in spin state in transition metal-based spin crossover (SCO) molecular complexes. Most time resolved experiments, performed by optical techniques, rely on the intrinsic light-induced switching properties of this class of materials. The optically driven spin state transition can be mediated by a rich interplay of complexities including intermediate states in the spin state transition process, as well as intermolecular interactions, temperature, and strain.

Influence of orbital two-channel Kondo effect on anomalous Hall effect in ferrimagnetic composites of LaNiO and CoFeO.

In this report, we have investigated the magnetoresistance (MR) and Hall effect of the ferrimagnetic composites containing LaNiO and CoFeO (CFO) (with CFO content 15% and 20%) which exhibit orbital two-channel Kondo (2CK) effect and therefore pronounced resistivity upturn at low temperature. Both composites manifest a negative to positive crossover in MR with increasing temperature. The MR is described by the Khosla and Fisher model of spin fluctuations scattering of conduction electrons and the two-band theory based on hybridized p-d sub-bands.

Tuning spin one channel to exotic orbital two-channel Kondo effect in ferrimagnetic composites of LaNiO and CoFeO.

We report the tuning from spin one channel to orbital two-channel Kondo (2CK) effect by varying CoFeO (CFO) content in the composites with LaNiO (LNO) along with the presence of ferrimagnetism. Although there is no signature of resistivity upturn in the case of pure LNO, all the composites exhibit a distinct upturn in the temperature range of 30-80 K. For composites with lower percentage of CFO (10%), the electron spin plays the key role in the emergence of resistivity upturn which is affected by external magnetic field.