  First- and second-harmonic dielectric susceptibilities are maidenly studied
on Samarium Orthoferrite of mesoscopic/500 nm and nanoscopic/55 nm grainsizes.
Magneto-electrically coupled to the antiferromagnetic and spin-reorientation
transitions, fundamental and harmonic dielectricity consistently reflect the
global/local polarization effects of crystallite-size dependent electrical
orderings. Bulk and incipient ferroelectricity respectively in nanoscopic and
mesoscopic crystallites concur the higher-temperature antiferromagnetic
ordering (T_N ~670 K). Upon the spin-reorientation transition at
lower-temperature (T_SR ~470 K), re-entrant relaxor state in the
nano-crystallites and bulk-like/temperature-windowed ferroelectricity in the
meso-crystallites emerge. In the nano-crystallites, magneto-electric signature
of interfacial spins' de-pinning (T_SP ~540 K) is exclusively revealed by the
scaled-harmonics.
