Traditional synthesis of high-performance bulk ferrites include complex sintering procedures where temperature and soak times to obtain high densities and excellent magnetic properties. Most ferrites must be sintered at hundreds degree centigrade approaching or surpassing 1000oC, and for YIG (yttrium iron garnet), the sintering temperature should be approximately 1450°C. The high sintering temperatures limit the applications of ferrites, for example, the low temperature co-sintering of ceramics with silver electrodes and/or ground planes. For decades, researchers have explored the use of ion-doping, sintering aids, and microstructural refinement. Here, we study the optimization of the sintering profile including multiples temperature and soak times for doped Bi-YIG simples. The results show an improvement in soft magnetic and gyromagnetic properties attributed to the homogenization of grain size and morphology.

A recent outbreak of Q fever was linked to an intensive goat and sheep dairy farm in Victoria, Australia, 2012-2014. Seventeen employees and one family member were confirmed with Q fever over a 28-month period, including two culture-positive cases. The outbreak investigation and management involved a One Health approach with representation from human, animal, environmental and public health. Seroprevalence in non-pregnant milking goats was 15% [95% confidence interval (CI) 7–27]; active infection was confirmed by positive quantitative PCR on several animal specimens. Genotyping of Coxiella burnetii DNA obtained from goat and human specimens was identical by two typing methods. A number of farming practices probably contributed to the outbreak, with similar precipitating factors to the Netherlands outbreak, 2007-2012. Compared to workers in a high-efficiency particulate arrestance (HEPA) filtered factory, administrative staff in an unfiltered adjoining office and those regularly handling goats and kids had 5·49 (95% CI 1·29–23·4) and 5·65 (95% CI 1·09–29·3) times the risk of infection, respectively; suggesting factory workers were protected from windborne spread of organisms. Reduction in the incidence of human cases was achieved through an intensive human vaccination programme plus environmental and biosecurity interventions. Subsequent non-occupational acquisition of Q fever in the spouse of an employee, indicates that infection remains endemic in the goat herd, and remains a challenge to manage without source control.

This study focuses on a Co-based nanocrystalline alloy (Co84.55Fe4.45Zr7B4) with potential for long-term high temperature use. As an indication of their performance, core losses were measured on toroidal samples using a Walker AC permeameter over a frequency range of 0.1 to 500 kHz, at induction amplitudes of 100, 300, and 500 mT, and temperatures from 22 to 300°C. For a given frequency and maximum induction amplitude, the losses were invariant as a function of measurement temperature. Vibrating sample magnetometry provided the magnetization and hysteretic losses as a function of temperature. As the temperature of the alloy was raised to 300°C from room temperature, the saturation magnetization (120 emu/g)was reduced by less than 15%. A toroid was aged at 300°C for up to 300 hours and core loss measured as a function of aging time at the previously mentioned frequencies and induction amplitudes. The losses were invariant over the aging time.

The magnetic properties of MnZn-ferrite are greatly affected by the distribution and valence state of the magnetic and nonmagnetic metallic ions on the tetrahedral (A) and octahedral (B) sites in the spinel ferrite unit cell. A primary factor which can affect the distribution and valence state of the metallic ions is the stoichiometry of the ferrite. In this paper we report on the results of the site occupancy of the transition metal ions in a series of MnZn-ferrite films using extended x-ray absorption fine structure (EXAFS). The EXAFS data are correlated with the film composition and those magnetic properties which are sensitive to the ionic distribution (e.g., magnetic anisotropy field and magnetization) in order to confirm the use of EXAFS as a technique for the investigation of metallic ion distribution in spinel ferrites.