In-plane c-axis oriented barium ferrite films with self-bias and low microwave loss

Abstract

Hybrid pulse laser deposition and liquid phase epitaxy methods have been used to produce in-plane c-axis (IPCA) oriented barium ferrite (BaM) films on a-plane (112¯0) sapphire substrates with low microwave loss and a high remanence. Total thicknesses were from 5to20μm. A reasonable compromise for low loss and high remanence was reached at a thickness of 7μm, with a remanence ratio of 0.84 and a 59GHz peak-to-peak derivative linewidth of 250Oe. The 20μm thick film had a linewidth of 110Oe, one of the smallest values ever obtained for IPCA BaM films.

M-Type Barium Hexagonal Ferrite Films

“…Note that the FWHM value is about 10% lower than that reported in Ref. [35]. These results clearly indicate that the film has a c-axis that is in the plane of the film and is highly oriented.…”

“…7,8,9,10,31,35,36 Sapphire is chosen because it has a rhombohedral crystal structure (a=5.128 Å and =5522′) which is close to the hexagonal structure of BaM; 31 and the mismatches of the lattice parameters and thermal expansion coefficients between sapphire and BaM materials are relatively small. 7,31,36 Certain device applications, however, require the growth of BaM films on conductive substrates.…”

“…Song et al reported "in-plane" BaM films with slightly lower M r /M s ratios at about 0.84, but with much narrower peak-to-peak linewidths of about 250 Oe. 35 Those films, however, were made through a hybrid process that involved both PLD and LPE methods along with post-deposition surface flux cleaning.…”

“…30 A variety of different techniques have been used to fabricate BaM film materials. These include pulsed laser deposition (PLD), 7,8,9,10,11,12,28,31 liquid phase epitaxy (LPE), 32,33,34,35 RF magnetron sputtering, 36,37,19,38,39,40 molecular beam epitaxy (MBE), 14 metallo-organic decomposition (MOD), 15 chemical vapor deposition (CVD), 41 and screen printing. 16,17 The device demonstration includes both numerical 20,21,22 and experimental efforts.…”

Structural and millimeter-wave characterization of flux grown Al substituted barium hexaferrite single crystals

“…Among them are thin-film technologies such as liquid phase epitaxy [26], pulsed laser deposition [27,28], screen printing technique [29], and metal organic decomposition [4]. The main methods for nano-and micro-particle synthesis are chemical co-precipitation method [30], hydrothermal reaction [31], sol-gel process [32], solution combustion technique [2], ceramic method [33], mechano-thermal treatment [34], and reverse microemulsion technique [35].…”