Magnetic properties of lithium ferrite microwave materials

This report presents a comprehensive review of the magnetic properties of lithium ferrite materials. The fundamental properties are considered first. These include crystal structure, magnetization, magnetocrystalline anisotropy, and magnetostriction. The extrinsic magnetic properties, which are related to microwave applications, are then examined. These include coercive force, remanence, and microwave loss. Finally, a systematic review of the effects of substituents, including titanium, zinc, manganese, cobalt, and bismuth, is presented.     

Submillimeter EPR evidence for the As antisite defect in GaAs

A new EPR spectrum has been observed in semi-insulating GaAs with a submillimeter laser magnetic resonance spectrometer. The spectrum is isotropic with g = 2.04 ± 0.01 at $\text{υ}\text{?}\text{= 11.236}\text{cm}{}^{\mathrm{-I}}$. The hyperfine interaction parameter | A | ($\text{[ =}\text{3}\text{2}$) is 0.090 ± 0.001 cm^-1. The spectrum is attributed to the As antisite defect in GaAs and the parameters are compatible with the P antisite defect in GaP.     

Block designs and graph imbeddings

Heffter first observed that certain imbeddings of complete graphs give rise to BIBD's with k = 3 and λ = 2 (and sometimes λ = 1); Alpert established a one-to-one correspondence between BIBD's with k = 3 and λ = 2 and triangulation systems for complete graphs. In this paper we extend this correspondence to PBIBD's on two association classes with k = 3, λ₁ = 0 and λ₂ = 2, and triangulation systems for strongly regular graphs. The group divisible designs of Hanani are used to construct triangulations for the graphs K_n(m), in each case permitted by the euler formula. Conversely, triangular imbeddings of K_n(m) are constructed which lead to new group divisible designs. A process is developed for “doubling” a given PBIBD of an appropriate form. Various extensions of these ideas are discussed, as is an application to the construction of quasigroups.