Towards laser additive manufacturing of magnetic ferrite: processing of yttrium iron garnet and potential applications to electronic components

The potential of laser based additive manufacturing is investigated to prepare 3D ceramic magnetic pieces starting from powder of yttrium iron garnet (YIG) type ferrites. This preparation technique is demonstrated to be successfully applicable to produce YIG ceramic samples for studying their magnetic and structural properties. Deposition of YIG is performed on several different substrates and some experimental conditions discussed. X-ray diffraction characterization allowed to observe the influence of laser sintering on the composition of the ferrite. A relative magnetic permeability of about μ r =44 is obtained for the produced prototype parts. Postdeposition heat treatment has been found to be efficient to improve the permeability of the printed ceramic. The performances of the laser manufactured ceramic parts have been tested in a wide frequency range up to 20 GHz, for different 2D or 3D devices such as magnetic core for toroidal inductor, waveguide isolator or coplanar isolators. Interestingly, non-reciprocal effect can be achieved at 12.4 GHz in a waveguide isolator and 10.8 GHz for a coplanar isolator. This study paves the way to an interesting manufacturing technique with high potential enabling to prepare complex geometries for high performance devices operating at high frequency (radio and microwave frequencies).