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A measurement system based on the colossal magnetoresistance CMR-B-scalar sensor was developed for the measurement of short-duration high-amplitude magnetic fields. The system consists of a magnetic field sensor made from thin nanostructured manganite film with minimized memory effect, and a magnetic field recording module. The memory effect of the La1−xSrx(Mn1−yCoy)zO3 manganite films doped with different amounts of Co and Mn was investigated by measuring the magnetoresistance (MR) and resistance relaxation in pulsed magnetic fields up to 20 T in the temperature range of 80–365 K. It was found that for low-temperature applications, films doped with Co (LSMCO) are preferable due to the minimized magnetic memory effect at these temperatures, compared with LSMO films without Co. For applications at temperatures higher than room temperature, nanostructured manganite LSMO films with increased Mn content above the stoichiometric level have to be used. These films do not exhibit magnetic memory effects and have higher MR values. To avoid parasitic signal due to electromotive forces appearing in the transmission line of the sensor during measurement of short-pulsed magnetic fields, a bipolar-pulsed voltage supply for the sensor was used. For signal recording, a measurement module consisting of a pulsed voltage generator with a frequency up to 12.5 MHz, a 16-bit ADC with a sampling rate of 25 MHz, and a microprocessor was proposed. The circuit of the measurement module was shielded against low- and high-frequency electromagnetic noise, and the recorded signal was transmitted to a personal computer using a fiber optic link. The system was tested using magnetic field generators, generating magnetic fields with pulse durations ranging from 3 to 20 μs. The developed magnetic field measurement system can be used for the measurement of high-pulsed magnetic fields with pulse durations in the order of microseconds in different fields of science and industry.

The powders of LiFePO 4 compounds have been synthesized by the solid state reaction, and LiFePO 4 /C composites were sintered in argon gas. The ceramics of LiFePO 4 were sintered in air. The surfaces of the ceramics were investigated by a scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDX). The binding energies of the Fe 2p, P 2p, and O 1s core level of LiFePO 4 ceramic and LiFePO 4 /C composite surfaces were determined by X-ray photoelectron spectroscopy (XPS). The deconvolutions of Fe 2p core level XPS are associated with Fe 2+ and Fe 3+ valence states of the ceramics. Impedance spectroscopy of the ceramics has been performed in the frequency range of 10 Hz to 3 GHz by low frequency and microwave impedance spectrometers. Two-and four-probe methods were used for measurements at low frequencies. The LiFePO 4 /C composite was investigated in nitrogen gas, and the measurements of LiFePO 4 were conducted in air. The measurements of the electrical properties of the ceramics were carried out in the temperature interval of 300-500 K.

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