Review—Goodenough-Kanamori-Anderson Rules-Based Design of Modern Radio-Frequency Magnetoceramics for 5G Advanced Functionality

Abstract

5th generation (5G) wireless technologies promise a transition from 4G 2.3 GHz to Ka-band (i.e., 28-33 GHz) frequencies and the promise of revolutionary increases in data handling capacity and transfer rates at greatly reduced latency, among other benefits. A key enabling 5G technology is the development of massive multiple input – multiple output (m-MIMO) antenna arrays. m-MIMO array elements simultaneously transmit and receive data providing true full duplexing in time and frequency domains. Small cells, i.e., mobile and stationary base stations used to supplement existing 4G network infrastructure to boost signals in dense urban environments, will provide coverage over smaller areas to efficiently transmit signals over the millimeter wave spectrum. In order to realize these extraordinary advances, key materials must be developed, chief among them RF magnetoceramics. Here, we describe application of the long-standing Goodenough-Kanamori-Anderson rules for superexchange as guiding principles in the design of next generation magnetoceramics to meet the challenges of 5G wireless communication technologies and their timely implementation.

Introducing Materials Science: Experimenting with Magnetic Nanomaterials in the Undergraduate Chemistry Laboratory

“…This in turn also determines the magnetic characteristics of the material, whereby normal spinels exhibit antiferromagnetism, and the inverse exhibit ferromagnetism, as described by the Goodenough-Kanamori rules. , One can predict which type of structure should be adopted by a given spinel (and thus its magnetic properties) based on a calculation of the crystal field stabilization energy (CFSE) resulting from each possible ordering of spins across the octahedral and tetrahedral sites, e.g., for magnetite (Fe II Fe III 2 O 4 ): Fe oct 3 + → ( 3 × 0.4 Δ oct ) − ( 2 × 0.6 Δ oct ) → CFSE = 0 Fe tet 3 + → ( 2 × 0.6 Δ tet ) − ( 3 × 0.4 Δ tet ) → CFSE = 0 Fe oct 2 + → ( 4 × 0.4 Δ oct ) − ( 2 × 0.6 Δ oct ) → CFSE = 0.4 normalΔ oct − normalP …”

“…This in turn also determines the magnetic characteristics of the material, whereby normal spinels exhibit antiferromagnetism, and the inverse exhibit ferromagnetism, as described by the Goodenough-Kanamori rules. 13 , 14 One can predict which type of structure should be adopted by a given spinel (and thus its magnetic properties) based on a calculation of the crystal field stabilization energy (CFSE) resulting from each possible ordering of spins across the octahedral and tetrahedral sites, e.g., for magnetite (Fe II Fe III 2 O 4 ): where Δ oct is the octahedral field stabilization energy, Δ tet the tetrahedral field stabilization energy, and P the spin pairing energy. Note that Δ oct is ×2.25 Δ tet , and so while there is no preference for where the Fe 3+ ions reside, the CFSE is maximized when Fe 2+ ions solely occupy the octahedral sites in the lattice.…”

Crystallographically Textured and Magnetic LaCu-Substituted Ba-Hexaferrite with Excellent Gyromagnetic Properties

“…Ferrite materials provide the necessary magnetic media to break time-reversal symmetry, allowing non-reciprocal behavior to passive control elements, such as circulators and isolators [1][2][3]. Despite progress over the past several decades, these devices remain comparatively large and heavy, mostly due to the external permanent magnets required to provide the necessary bias fields to saturate the ferrite.…”

“…Broadband, low-loss properties are prerequisites for high-performing, high-frequency, and self-biased MMW devices based on crystallographically textured Ba-hexaferrites [3]. Improved remanent magnetization, 4πM r , and narrow ferromagnetic resonance linewidths, ∆H FMR , allow for the reduction in resonance losses [8] and optimized anisotropy fields, H a .…”