Photoinduced changes of magnetic anisotropy in substituted iron garnet

Photomagnetic Medium as Weak Magnetic Field Sensor

“…during the measurements) don't changes magnetocrystalline MA. Only variations of the axis orientation and constant of the photoinduced MA are observed [5].…”

“…The exposure by linearly polarized light leads to an appearance or change of the combine (cubic and uniaxial photoinduced) MA in the doped yittrium iron garnet (YIG) [5]. Photoinduced MA occurrence selects an easiest MA axis that is coincided with E direction.…”

“…At exposure of the prior irradiated sample local region with M that is directed along crystallographic [ 1 11 ] direction by the linearly polarized light with k 0 and Е those are directed respectively along crystallographic [ 0 1 1 ] and [ 11 1 ] directions, the photoinduced MA energy density [5] is given by (fig. 3):…”

“…, λ is a Solid State Phenomena Vol. 230 constant of spin-orbital coupling; F N is a total amount of redistributed medium active centers [5], V is limited by the boundaries 0 r and ỳ 0 in the light spot cross-section and along light propagation direction respectively. The region boundaries are defined by the solutions of equations V and maximum photoinduced MA energy density value respectively (fig.…”

“…) where 1 K is a medium magnetic anisotropy (МА) constant, M is a medium saturation magnetization, D α is a coefficient that depends on MD linear sizes D R and D L and also MA energy constant reduction 1 K ∆ in MD volume, N is a demagnetizing factor. An optical exposure by linearly polarized radiation of the photomagnetic magnetically ordered medium leads to change of its magnetocrystalline MA energy and appearance of a combine (magnetocrystalline and uniaxial photoinduced) MA in the irradiated sample volume [5]. Operation principle of the photomagnetic medium as magnetic field sensor is based on local photoinduced change of the medium MA energy density in irradiated volume and achievement of an equality of the nucleation field n H and measured magnetic field H in which sample is placed.…”