Abstract. A new technique of inductive measure to determine the initial magnetic permeability (r) of Yttrium Iron Garnet (YIG) thin films has been conceived and developed in our laboratory. The magnetic material is deposited by radio-frequency sputtering between two copper thin layers on alumina substrate. Because the as-deposited films are amorphous and non magnetic, thermal annealing is necessary to make the films crystallize and to obtain satisfactory magnetic properties. After different tests considering the geometrical, morphological and magnetic properties, we have established a protocol permitting to manufacture a prototype in an original design. The performance of the fabricated micro-inductor has been checked using a physical-chemistry characterization. To obtain accurate measurements, we have used a four-point probe test bench and a precision LCR meter. The current sheet method has been validated with thick layers of commercial YIG. The results obtained for thick and thin films of YIG have been compared to the simulation and theoretical ones. Several tests, made for different thickness and different number of loops, have permitted us to evaluate the magnetic permeability of YIG thin films to 32 ± 4.

Abstract. The Yttrium Iron Garnet (YIG) is chosen by our laboratory for the integration of passive components in the microwaves domain and for the miniaturization of integrated inductors and transformers. Magnetic and morphological characterizations are essential for the development of these components. To fabricate a micro-inductor of solenoid type, we have deposited on an alumina substrate, by RF sputtering, a thin YIG film between two layers of copper. We have also used the photolithography technique in a clean room to obtain the desired pattern of the coil. The YIG films are amorphous after deposition, the annealing at 740°C for 2 hours is necessary for them to be crystallized and to have magnetic properties. To avoid the deterioration of copper layers, the Classical Thermal Annealing (CTA) was replaced by a Vacuum Thermal Annealing (VTA). Before manufacturing the integrated inductor, it is interesting to do the magnetic, crystallographic and morphological characterizations of YIG films after annealing with both techniques of thermal treatment. To check the quality of the prototype, we have done different characterizations: VSM, Kerr effect, XRD, SEM. The results obtained with VTA were better than of CTA comparing them with bulk YIG properties.

International audienceThe aim of our study is to characterize yttrium iron garnet (YIG) thin film for its applications in the microwaves and magnetooptical domains. For this purpose, we have manufactured a microinductor by deposition of YIG film between two copper layers on an alumina substrate. Multilayers have been deposited by radio-frequency magnetron sputtering technique. Thin films of YIG are amorphous after deposition; a post-thermal annealing at 740 8C for 2 h is necessary to obtain satisfactory magnetic properties. In this work, we have studied the effects of different parameters concerning the substrate surface state, deposition and post-thermal treatment of YIG and copper thin films on their structure and morphological properties. We have come against several mechanical and electrical problems: crack formation, detachment of YIG or Cu films from the substrate, deterioration of Cu films, open or short circuits. The roughness of alumina substrate and the annealing mode play an important role on the quality of themicroinductor prototype. After several tests by varying different parameters, we have established a protocol permitting to manufacture a prototype of good quality. This prototype is characterized using: profilometry, scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and a precision LCR meter