Photomagnetic Anneal Properties of Silicon-Doped Yttrium Iron Garnet

Abstract

Torque measurements have been made at 4.2°K on crystals of silicon-doped yttrium iron garnet which were irradiated with infrared light. The radiation caused large photomagnetic anneal effects which were found to depend on the plane of polarization of the light.

Design of a Novel Magnet Exhibiting Photoinduced Magnetic Pole Inversion Based on Molecular Field Theory

“…For example, magnetic materials exhibiting giant magnetic resistance effects open a new avenue in the field of magnetic memory devices. , Our objective in the present work is to control magnetic properties by photostimuli. The first observation of photoinduced magnetic effects was reported with Si-doped yttrium iron garnet (YIG) 30 years ago. − In this system, the initial permeability and coercive field were changed by photoirradiation. Conversely, we have recently reported a photoinduced enhancement of magnetization in K 0.4 Co II 0.3 Co III [Fe II (CN) 6 ]·5H 2 O. , In this material, the electron-transfer proceeds from Fe II ( S = 0) to Co III ( S = 0) by visible light irradiation, producing Fe III ( S = 1/2)−CN−Co II ( S = 3/2).…”

Photoproduction of long-lived holes and electronic processes in intrinsic electric fields seen through photoinduced absorption and dichroism in Ca3Ga2 xMnxGe3O12garnets

“…Long-lived photoinduced phenomena in magnetic insulators were observed by many research groups [1][2][3][4][5][6][7][8][9][10][11][12][13] and associated with the photoinduced transfer of charges. In ferromagnets or ferrimagnets, whose Curie temperature exceeds the upper temperature boundary of the existence of long-lived photoinduced phenomena, interrelated photoinduced changes in optical and magnetic properties make up a complicated physical picture difficult for microscopic interpretation.…”

“…In ferromagnets or ferrimagnets, whose Curie temperature exceeds the upper temperature boundary of the existence of long-lived photoinduced phenomena, interrelated photoinduced changes in optical and magnetic properties make up a complicated physical picture difficult for microscopic interpretation. For example, the illumination of yttrium iron garnet Y 3 Fe 5 O 12 0953-8984/03/234025+20$30.00 © 2003 IOP Publishing Ltd Printed in the UK with linearly polarized light induces a change of magnetic anisotropy [1][2][3], linear dichroism [3] and domain structure [4]. Unpolarized light affects magnetic permeability and susceptibility [5,6], coercivity and mobility of domain walls [7,8], magnetostriction [9] and optical absorption [10,11].…”

“…Based on this information, several questions should be answered: (1) In what way do electric fields of photoproduced holes enhance the oscillator strength of the optical transition serving as a probe for these fields? (2) In what way do pumping photons, being absorbed within a specific absorption band, create long-lived holes? (3) What is the mechanism of the relaxation (disappearance) of photoproduced holes?…”

“…The forbiddenness is partially eliminated by an electric field that imparts an odd addition to even states. (2) The photoproduction of charges was associated with a small impurity of Mn 4+ ions in the Mn 3+ sublattice. In the ground state, these Mn holes are pinned near Ge vacancies bearing a compensating negative charge; light pumping of the Mn sublattice results in a partial separation of these positive and negative charges and in the corresponding enhancement of their electric field.…”