Thermomagnetic Recording in Thin Garnet Layers

Abstract

Thermomagnetic flux reversal has been studied in single‐crystal layers of Y₃Ga_1.1Fe_3.9O₁₂ with 5‐μm thickness, prepared by liquid‐phase epitaxy (LPE) on a (111) Gd₃Ga₅O₁₂ wafer. By structuring the layers in a checkerboard pattern of squares with 10‐μm periodicity and 2‐μm width and depth of the surface grooves, arbitrary stable domain patterns have been obtained. Individual squares have been switched magnetically using heat pulses from a laser beam of 20‐mW intensity at 5145‐Å wavelength with fields as low as 13 Oe in case of a nearly demagnetized domain distribution. The beam energy for reversing the magnetization of a square is below 1 erg.