Ferrite films for microwave and millimeter-wave devices

Abstract

For microwave and millimeter-wave applications, there is increasing interest in using ferrite films rather than bulk ferrites. In some cases, such as magnetostatic wave devices, films provide definite performance advantages. In other cases, films may provide lower cost, smaller size, and enhanced compatibility with planar circuit designs such as monolithic microwave integrated circuits (MMlC). The relatively limited research on ferrite films for microwave and millimeter-wave applications has borrowed from the more extensive work that has been motivated by applications to various forms of magnetic recording. An example is the YlG (yttrium iron garnet) epitaxial film, brought to a high level of development as a by-product of bubble memory technology and now coming into use for tunable microwave filters and for magnetostatic wave devices. Similarly, other magnetic recording materials point the way to development of ferrite films suitable for other microwave and millimeter-wave applications including, eventually, fully monolithic incorporation into MMlC technology.

Site occupancy and magnetic study of Al3+ and Cr3+ co-substituted Y3Fe5O12

“…Since its discovery in 1956, yttrium iron garnet (YIG) and substituted-YIG have attracted a lot of attention because of their application in microwaves domain [1] and magneto-optical devices [2]. YIG has the chemical composition {Y 3 [3] and in the trigonal space group R3 by Rodic et al [4], to account for the lowering of symmetry due to spontaneous magnetostriction.…”

Spectral shape deformation in inverse spin Hall voltage in Y3Fe5O12|Pt bilayers at high microwave power levels

“…In the uniform precession mode at low microwave power, the microwave absorption intensity follows a Lorentzian function, 13,14 which is reflected by the ISHE voltage signal. 6,9 The ferrimagnetic insulator yttrium iron garnet (Y 3 Fe 5 O 12 , YIG) 15 is a commonly used spin injector. The low magnetic loss at microwave frequencies (damping constant 3 × 10 −5 ) 16 , as well as highly insulating properties (band gap 2.85 eV) 17 make it ideal for the transport and manipulation of pure spin currents.…”

Microstructure and magnetic properties of CoFe2O4 thin films deposited on Si substrates with an Fe3O4 under-layer

“…The decreasing annealing temperatures are ascribed to phase transformation of the Fe 3 O 4 under-layer at about 400°C-500°C to accelerate the crystallization of cobalt ferrite films. The low annealing temperature of spinel ferrite films is especially important for its application in Monthnic Microwave Integrated Circuits (MMIC) [16]. The crystallization process of ferrite films with Fe 3 O 4 under-layers deserves to be studied further.…”