[en] In this work, a new type of asymmetrical magnetoimpedance (AMI) effect has been found in a new type of NiFe/SiO₂/Cu composite wire without applying any dc-biased magnetic field, in which NiFe/SiO₂/Cu composite wires were fabricated by sputtering a NiFe seed layer on the SiO₂ layer and then electroplating another NiFe layer on the NiFe seed layer. A magnetization rotation model based on the coupling effect with bias field in the seed layer and the pinning effect by defects in the wire has been used to qualitatively explain the AMI profiles observed.

[en] Cluster free, Co (3d) and Eu (4f) doped ZnO thin films were prepared using ion implantation technique accompanied by post annealing treatments. Compared with the mono-doped ZnO thin films, the samples codoped with Co and Eu exhibit a stronger magnetization with a giant coercivity of 1200 Oe at ambient temperature. This was further verified through x-ray magnetic circular dichroism analysis, revealing the exchange interaction between the Co 3d electrons and the localized carriers induced by Eu³⁺ ions codoping. The insight gained with modulating coercivity in magnetic oxides opens up an avenue for applications requiring non-volatility in spintronic devices

[en] We report the magnetic and magnetotransport properties of (In_0.985Nd_0.015)₂O_2.89 thin films grown by pulse laser deposition. The clear magnetization hysteresis loops with the complementary magnetic domain structure reveal the intrinsic room temperature ferromagnetism in the as-prepared films. The strong sp-f exchange interaction as a result of the rare earth doping is discussed as the origin of the magnetotransport behaviours. A positive magnetoresistance (∼29.2%) was observed at 5 K and ascribed to the strong ferromagnetic sp-f exchange interaction in (In_0.985Nd_0.015)₂O_2.89 thin films due to a large Zeeman splitting in an external magnetic field of 50 KOe.

[en] We present the results of a systematic investigation of the dc magnetization, ac susceptibility, resistivity and thermopower of Pr_2-xSr_xCoO₄ (x = 1.2, 1.3 and 1.5). The x = 1.2 specimen undergoes a paramagnetic phase above 201.57 K, Griffiths phase between 201.57 and 129.24 K, ferromagnetic cluster-glass phase between 129.24 and 16.19 K and spin-glass state reentrance below 16.19 K. With increasing Sr content, the Griffiths phase and the spin-glass state are suppressed. The specimen shows a p-type semiconducting conduction changing from thermally activated conduction to variable range hopping conduction with increasing Sr doping level. The rich magnetic and transport behaviors are suggested due to the complicated magnetic interactions and Jahn-Teller distortion of the cobalt ions associated with small polarons

[en] The emission behavior of C-doped ZnO films, which were prepared by implantation of carbon into ZnO films, is investigated. Orange/red emission is observed for the films with the thickness of 60–100 nm. However, the film with thickness of 200 nm shows strong green emission. Further investigations by annealing bulk ZnO single crystals under different environments, i.e. Ar, Zn or C vapor, indicated that the complex defects based on Zn interstitials are responsible for the strong green emission. The existence of complex defects was confirmed by electron spin resonance (ESR) and low temperature photoluminescence (PL) measurement

[en] To enhance the performance of weak magnetic field sensors such as magneto-impedance (MI) effect sensors or orthogonal fluxgate sensors, the magnetic permeability of the ferromagnetic sensing elements has to be increased. In this study, the effects of annealing on the magnetic properties and sensing performance of cold-drawn Ni₈₀Fe₂₀/Cu wire sensing element have been investigated. The Ni₈₀Fe₂₀/Cu wire specimens were cold-drawn to a diameter of 34 μm and were annealed at different temperatures. The effects of final annealing temperature on the anisotropy, coercivity and MI effect of the composite wires were investigated. The results showed that the permeability increased with increasing annealing temperature until a critical value, and then decreased drastically with further increase in the annealing temperature. The decline in permeability and MI effect with further increasing annealing temperature were attributed to grain growth in the NiFe and diffusion between the NiFe and Cu. Sensitivity of the sensors with the annealed cold-drawn Ni₈₀Fe₂₀/Cu wires showed the same trend as that of permeability

[en] In this study, CoNiFe/Cu composite wires were deposited using electroplating. The deposited material composition was controlled by adjusting the concentration of Co ions. The results showed that the surface morphology and particle size did not change much with different compositions. However, the coercivity of the composite wires varied significantly for different compositions. A magnetic layer, with the composition of Co₃₀Ni₅₀Fe₂₀, was found to possess a low coercivity value of 0.65 Oe. This is due to the low magneto-strictive factor for the alloy with this composition. In addition, the results showed that the concentration of Fe ions played an important role in achieving low coercivity and high magneto-impedance (MI) effect in the CoNiFe/Cu wires