Magneto-impedance Effects in Electrodeposited Multi-layer [NiFe/Cu]3 on Cu Wire Substrates for kHz-order Frequency Measurements

The magneto-impedance effect (MI) in an electrodeposited multi-layered system of [NiFe/Cu]N on a Cu wire was modified by varying the thickness of the Cu spacer layer. The multi-layered samples of [NiFe/Cu]N were deposited by the electrodeposition using a platinum electrode. The MI ratio rapidly increased with a frequency of up to 100 kHz where it saturated. Conversely, the MI ratio of the multi-layered system [NiFe (800 nm)/Cu(y nm)]3 was a decreasing function of Cu layer thickness. The decreased MI ratio may be attributed to the lowered saturation magnetization in the multi-layered system with thicker spacer layers.

Effect of La-Substituted Barium Hexaferrite on the Structural Characteristics and Magnetic Properties for Microwave Absorbing Material

Ba1-xLaxFe12O19 with ion substitution La3+ (x = 0 – 0.7) has been produced via the mechanical milling technique of the solid reaction method. Considering that Ba1-xLaxFe12O19 is expected to be used as a microwave absorbent, it is necessary to characterize its structural and magnetic features. The refinement results of the X-ray diffraction (XRD) data show that a single-phase hexagonal structure (space group P63/mmc) is obtained for x = 0 and x = 1, while for the composition of x 0.1 is multiphase. The lattice parameters and crystal volume decreased, whereas the lattice strain was found to advance with increasing La substitution in the sample. For x = 0.1, the crystallite size is constant while the lattice strain increases. Employing a scanning electron microscope (SEM), the observation of particle morphology shows that the single-phase (x = 0 and x = 0.1) has a comparably unvarying particle size circulation, while for x 0.1, different particle shapes and sizes are found. The saturation magnetization raises while the coercivity field reduces due to the substitution of La for x = 0.1. Furthermore, for x 0.1, the saturation magnetization decreases while the coercivity field increases.

Local Structure and Magnetism of LiFeSi0.01P0.99O4/C as a Cathode Material on Lithium-Ion Battery

The oxidation state and local structure of LiFeSi0.01P0.99O4/C composites as a cathode on lithium-ion battery were investigated by Fe K-edge X-ray Absorption Near Edge Spectroscopy (XANES) and Extended X-ray Absorption Fine Structure (EXAFS). The LiFeSi0.01P0.99O4/C sample was prepared by solid-state reaction process. Based on the XANES analysis, the absorption of edge energy (E0) of the sample was 7124.92 eV. In addition, linear combination fitting (LCF) analysis of XANES confirmed the oxidation state of iron mixture of 2+ and 3+ as the effect of silicon doped in LiFePO4. The Fourier Transform (FT) of the Fe K-edge EXAFS fitting analysis showed that the nearest neighbors surrounding atom Fe were the main peak with high intensity that confirmed Fe-O bond; the second and third peak with lower intensity confirmed Fe-P and Fe-Fe bonds, respectively. In addition, the SQUID magnetometer result of LiFeSi0.01P0.99O4/C indicated the antiferromagnetic order temperature of LiFeSi0.01P0.99O4/C at ~51 K with the indication of the presence of impurity and structural distortion.

Detail Synthesis Route of Free-Standing Antiferromagnetic La2CuO4 Nanoparticles via Sol-gel Method

We report the detailed synthesis route of free-standing antiferromagnetic La2CuO4 nanoparticles by the sol-gel method. The precursors were needed to be dissolved in acid solution and continued with heating treatment to make a gel. Some catalyst was needed to control and stabilized the transformation from the solution to gel. Some heating treatments were also conducted to remove the organic component and for the nucleation process to obtain the single-phase sample. Although the sol-gel method required some additional precursors such as acid and catalyst, it has some advantages. It needed a relatively low sintering temperature and short sintering time compare to those at the solid-state reaction. Interestingly, this method can produce a sample with a good distribution of the particle size.

Specific Heat on Single-crystalline YVO3

The specific heat of single-crystalline YVO3 was measured from 2 K up to 250 K at zero field. The results reveal three transitions, at around 75, 115, and 200 K. The transitions at around 115 K and 200 K show that the phase transition is of the second-order type, whereas at around 75 K, unusual features of the specific heat are found. These unusual features are attributed to the effect of a large change in the volume. The specific heat data were analyzed in terms of a lattice contribution, a Schottky contribution and an excess magnetic contribution at high temperature. The magnetic contribution well above the magnetic ordering temperature is ascribed to short-range interactions due to the presence of strong magnetocrystalline anisotropy. The magnetic entropy considered by using this approach is 9.13 J/mole K which is close to the theoretical estimate for the S = 1 system.