INPLANE MAGNETIZED YIG SUBSTRATES SELF-BIASED BY SMCO BASED SPUTTEREDFILM COATINGS

Highly anisotropic SmCo based films with the TbCu7-type structure have been sputter deposited directly onto YIG substrates. The SmCo crystal lites have the c axes approximately randomly splayed about the substra te plane such that the easy direction of magnetization of the SmCo fil m is in the film plane. The in-plane static energy product of the SmCo film layers was about 16 MG Oe. In-plane vibrating sample magnetomete r hysteresis loops of the SmCo film and YIG substrate exhibit a compos ite form with the YIG field reversal shifted into the first quadrant b y the looping field from the SmCo film layer. Approximately 4X4 mm(2) pieces of YIG substrate have been measured to determine the YIG bias f ield and field required for reverse saturation of the YIG as a functio n of the SmCo based film layer thickness to YIG substrate thickness. I t is observed that for SmCo to YIG thickness ratios greater than 0.22, the looping field from the SmCo film layer is sufficient to saturate the YIG magnetization in the reverse direction. SmCo film thicknesses in the range from 80 to 120 mu m have been used in these studies. Spec ial boundary layers have been used to promote thick film adhesion to t he YIG substrates.