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Fe-substituted YFe x Cr 1-x O 3 crystalline compounds show promising magnetic and multiferroic properties. Here we report the synthesis and characterization of several compositions from this series. Using the autocombustion route, various compositions (x = 0.25, 0.50, 0.6, 0.75, 0.9, and 1) were synthesized as high-quality crystalline powders. In order to obtain microscopic and atomic information about their structure and magnetism, characterization was performed using room temperature X-ray diffraction and energy dispersion analysis as well as temperature-dependent neutron diffraction, magnetometry, and 57 Fe Mössbauer spectrometry. Rietveld analysis of the diffraction data revealed a crystallite size of 84 (8) nm for YFeO 3 , while energy dispersion analysis indicated compositions close to the nominal compositions. The magnetic results suggested an enhancement of the weak ferromagnetism for the YFeO 3 phase due to two contributions. First, a high magnetocrystalline anisotropy was associated with the crystalline character that favored a unique high canting angle of the antiferromagnetic phase (13°), as indicated by the neutron diffraction analysis. This was also evidenced by the high magnetic hysteresis curves up to 90 kOe by a remarkable high critical coercivity value of 46.7 kOe at room temperature. Second, the Dzyaloshinskii-Moriya interactions between homogenous and heterogeneous magnetic pairs resulted from the inhomogeneous distribution of Fe 3+ and Cr 3+ ions, as indicated by 57 Fe Mössbauer studies. Together, these results point to new methods of controlling the magnetic properties of these materials.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is one of the biggest public health issues in the last years. The WHO has reported more than 50,000 confirmed cases and more than 1,000,000 confirmed deaths around the world. Early diagnosis is essential for an appropriate patient care and infection control, so laboratory where molecular tests are held plays a main role. However, laboratory facilities for testing are limited in rural areas. Therefore, it is important to have an effective and practical point-of-care diagnostic system in order to be implemented in developing countries with limited energy access. The objective of this research is to develop an energetically autonomous point-of-care diagnostic system for molecular detection of SARS-CoV-2. This design consists of a retractable system with an area of 15.79 m 2 and 3 well-distributed interior areas to guaranty appropriate sample processing. Our point-of-care diagnostic system can be installed at a fixed place (stationary), and it can also be transported to various strategic places (itinerant). The off-grid photovoltaic system feasibility was evaluated using the PVsyst software, presenting an installed capacity of 2.79 KWp, consisting of 4 monocrystalline photovoltaic modules, a 45 A charge regulator and 4 batteries (6 V, 453 Ah). The results showed a performance ratio of 0.522, with higher losses by the full battery (31.77%). This research determines that the proposed point-of-care diagnostic system meets all requirements to set and operate molecular techniques to diagnose infectious diseases, such as COVID-19, with good laboratory conditions, secure and eco-efficient energy, supporting the health scheme to prevent and control the spread of the virus., Competing Interests: Conflict of interestNot applicable., (© The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature 2021.)