{'fraction_non_alphanumeric': 0.02763819095477387, 'fraction_numerical': 0.02135678391959799, 'mean_word_length': 5.083969465648855, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Nonlinear Optical Study of Phase Transition in Lead Magnesium Niobate

The second harmonic (SH) intensity generated in relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 (PMN) was measured using ceramic samples in field-cooling and field-heating after zero-field-cooling processes in the temperature range from 100 to 300 K. Even in the zero-field-cooling process, the SH intensity was observed to increase steeply at about 240 K and saturate near 150 K. This phenomenon can be interpreted by the incoherent summation of the SH amplitude due to scattering by grain boundaries. The behavior also confirms that a polar rhombohedral region develops in the cubic perovskite matrix with decreasing temperature. The non-ergodic behavior was also observed in different cooling/heating paths under an electric field.