Microstructure, mechanical and magnetic properties of YIG/YIG homogeneous joints with lossless magnetic transmission fabricated by a novel Bi2O3-B2O3-BaO-Fe2O3 magnetic glass-ceramic

In this article, we designed a novel Bi 2 O 3 -B 2 O 3 -BaO-Fe 2 O 3 (BBBF) magnetic glass-ceramic braze with various Fe content to fabricate YIG ferrite. • The network structure, thermal properties, crystallization behavior, magnetism of the glass braze were systemically reported. • YIG/BBBF glass /YIG joints showed desirable mechanical reliability and magnetic performance by controlling the in-situ crystallization of target phase BaFe 12 O 19 . • The highest shear strength of the joints was 62.6 MPa and the maximum of the joints' saturation magnetization intensity was 28.01 emu/g (over 97% of the base material), which is the first time that the magnetic performance of YIG/YIG joint has reached such a level. • We have revealed the regulation mechanism of the target magnetic phases on the magnetic performance of the joints, providing a theoretical basis for further improving the performance of functional device. A new designed Bi 2 O 3 -B 2 O 3 -BaO-Fe 2 O 3 magnetic glass-ceramic braze was developed to fabricate yttrium iron garnet ferrite (YIG) integrated structure. The magnetism level of the glass braze was controlled by in-situ crystallization of magnetic phase BaFe 12 O 19 and transitional phases. The saturation magnetization intensity of the glass brazes reached its maximum of 7.83 emu/g after designed heat-treatment for crystallization. YIG/BBBF glass/YIG joints showed not only outstanding mechanical strength but also desirable magnetic performance. The shear strength of the joints was up to 62.6 MPa, and the saturation magnetization intensity of the joints was up to 97% of YIG base material, which indicated almost no attenuation of the joints' magnetic performance compared with YIG base material. The mechanisms of the target magnetic phase BaFe 12 O 19 on the mechanical and magnetic performance of the joints were deeply elaborated, laying theoretical foundation for the magnetic control of ferrite device joints.