Yttrium (Y3+)-substituted strontium hexaferrite nanoparticles with composition SrFe12-x Y x O19 have been synthesized using the sol-gel method. Diverse analytical tools have been applied to characterize the prepared strontium hexaferrite nanoparticles and to analyse the influence of yttrium (Y3+) substitution on the structural and magnetic properties. X-ray diffraction patterns confirm the presence of single phase M-type hexagonal crystalline structure. In fourier-transform infrared spectroscopy, the absorption bands at low wavenumber confirmed the formation of hexagonal ferrites. The vibrating sample magnetometer has been employed to study the magnetic behavior of Y3+ ions substituted strontium hexaferrite. The decrease in saturation magnetization (Ms) and coercivity (Hc) value has been explained on the basis of alteration in magnetic interactions due to the replacement of both Fe3+ ions by the non-magnetic Y3+ ions.

High resolution spectroscopy of doped molecules in He nano-droplets and clusters gives a signature of superfluidity in microscopic system, termed as microscopic superfluidity. Ro-vibrational spectrum of HeN-M clusters is studied with the help of some important observations, revealed from experiments (viz., localised and orderly arrangement of He atoms, although, being free to move in the order of their locations; individual He atoms can not be tagged as normal/ superfluid, etc.) and other factors (e.g., consideration that the 4 4 4 4 4 He atoms which happen to fall in the plane of rotation of a molecule, render a equipotential ring and thus, do not take part in rotation; etc.) which effect the rotational and vibrational spectrum of the system. This helps us in successfully explaining the experimental findings which state that the rotational spectrum of clusters have sharp peaks (indicating that the molecule rotates like a free rotor) and moment of inertia and vibrational frequency shift have a non-trivial dependence on N.

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