Reversible and Irreversible Relaxation of Magnetic Permeability in Photoexcited Yttrium Iron Garnet

Abstract

Photoinduced variation of magnetic complex permeability µ=µ'-jµ'' at low frequency, e.g., 0.14 kHz is studied as a function of temperature in yttrium iron garnet (YIG). We have observed a new phenomenon in YIG occurring solely after illuminated at low temperature; photoinduced disaccommodation. We discussed an origin of the observation, taking account of the charge state of oxygen vacancy and an interaction between lattice relaxation and domain wall.

Mechanism of Photoinduced Disaccommodation in Yttrium Iron Garnet

“…It is confirmed experimentally that these minima of p" in Fig. 1 are due to photoinduced DA [7]. In order to explain these results, we correlate these features with an existence of so-called F-center.…”

“…In all samples,however, a considerable oxygen vacancy is incorporated of the order of 0.001 mol estimated from spectroscopic method [7].…”

“…Source of irradiating the samples was a xenon lamp, since no conspicuous differences among the many kinds of light sources such as laser light [7], LED, mercury light , X-ray [8] and or gamma-ray[9] employed in these.…”

Thermal Hysteresis of Photoinduced Magnetic Effect in Yttrium Iron Garnet

“…In several samples, an additional DA peak independent of irradiation is observed around room temperature, the reason of which may be ascribed to oxygen vacancy with double electrons trapped [5]. These results are interpreted within the context of configuration coordinate(CC) diagrams with large lattice relaxations [6]. In this case the photoexcitation energy is larger than leV while the thermal energy for recovery process is less than 0.1 eV.…”