We report 77 Se-NMR measurements in the recent discovered K0.8Fe2Se2 with the superconducting transition temperature Tc = 32 K. The characteristic point of this system is that the high density of state is located in the vicinity of the Fermi level. The comparison between Knight shift and nuclear spin lattice relaxation rate 1/T1 shows that the antiferromagnetic spin correlation is not strong in this system, but it is reasonable to consider that its development toward low temperatures occurs. 1/T1 in the superconducting state can be reproduced well by an s ± -wave model, but a d-wave model also roughly reproduces the data. Non exponential behavior in 1/T1 at low temperatures disagrees with a single isotropic gap.

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We have investigated the magnetic properties in the well localized compound NdFe 2 Al 10 and the Kondo semiconductor CeT 2 Al 10 (T = Ru, Os) to clarify the origin of the unusual magnetic order in CeT 2 Al 10 . In NdFe 2 Al 10 , the experimental results of the magnetic properties could be reproduced very well by the mean-field calculation for the two-sublattice model. In CeT 2 Al 10 we could reproduce the anisotropic magnetic susceptibility in the paramagnetic region above 60-100 K very well by the mean-field calculation for the two-sublattice model introducing an anisotropic exchange interaction and the recently determined crystalline electric field (CEF) level scheme from Strigari et al. [Phys. Rev. B 86, 081105 (2012)]. However, in the antiferromagnetic (AFM) ordered state, we could not reproduce the experimental results at all in the framework of the mean-field calculation for the two-sublattice model. We propose that although the magnetic properties in the paramagnetic region above 60-100 K could be understood well by a localized picture, the ordered state could not, and that the c-f hybridization, especially along the a axis, is associated with the unusual magnetic order in CeT 2 Al 10 .

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