EFFECT OF CO60 GAMMA-RAY IRRADIATION ON PHASE TRANSITIONS IN NANO2

Single crystals of NaNO2 were irradiated with Co60 gamma-ray of 1–6×108 R at room temperature, then the dielectric constant ε22 was measured in the vicinity of the transition temperatures. Both the ferroelectric to sinusoidal transition point (the Curie point) and the sinusoidal to paraelectric transition point (the Néel Point) monotonically decreased with gamma-ray irradiation. The ratio of the initial decreasing rate of the Curie point to that of the Néel pint is 1.21. The sinusoidal phase widens with irradiation up to 2.5×108 R, then it narrows with more irradiations. The transitions become sluggish with irradiation dose more than 2.5×108 R. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.