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SmFeSiC thin films have been obtained by sputtering SmFe/C(Si) multilayers with a Ta underlayer on Si substrates and subsequently annealing at 700 [degrees] C. The coercivity of the SmFeSiC films strongly depends on the sputtering and annealing conditions. The influence of the thickness of the Ta underlayer, the thickness ratio of SmFe to C(Si), the argon pressure and heat treatment In- plane coercivities up to 7.2 kOe and squareness of 0.94 were obtained.

The melt-spun method helps prepare magnetic granular CoCu alloy ribbons suitable for making isotropic magnetic field transducers. X-ray diffraction studies help study the structure of CoCu alloy ribbons. Annealing temperature exerts a strong influence on the relationship of magnetoresistance (MR) with magnetic field H, with a linear MR-H relationship at optimum annealing conditions. Direction between H and electric current I exerts no influence on the MR ratio.

The magnetocaloric effects (MCEs) of La[Fe.sub.13-x][Si.sub.x] compounds doped by magnetic rare earths (R = Ce, Pr and Nd) and transition metal (Co) are studied. The analyses have shown that refrigerants made of La[Fe.sub.13-x][Si.sub.x] have as low as possible Si content and proper Co content simultaneously.

An oxide bilayer junction has been fabricated by growing a La[sub 0.32]Pr[sub 0.35]Ca[sub 0.33]MnO[sub 3] film on 0.5 wt % Nb-doped SrTiO[sub 3] crystal, and its behavior under magnetic field is experimentally studied. It is found that external field greatly affected the rectifying property and the resistance of the junction, causing an extremely large magnetoresistance. The most striking observation of the present work is that the magnetoresistance of the junction can be either positive or negative, depending on temperature and applied current, and is asymmetric with respect to the direction of the bias current. These results reveal the great potential of the manganites in configuring artificial devices. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: In NaZn13-type Pr z La1−z (Fe1−y Co y )11.8Si1.2 () compound, besides adjusting the phase transition temperature to room temperature after the substitutions of Pr for La and Co for Fe, the character of magnetic first-order phase transition is strongly reduced. Thus, the hysteresis losses hardly exist in these compounds. Meanwhile, a large magnetic entropy change about 13.6–15.7 J/(kg K), superior to that of Gd, is obtained in 0–5 T field change. So, these compounds are suitable candidates for magnetic refrigerant near room temperature. [Copyright &y& Elsevier]

Abstract: For the Nd0.1La0.9Fe11.5Al1.5 compound, the fine structure of the magnetic transition from the ferromagnetic (FM) to the antiferromagnetic (AFM) states has been studied carefully by means of magnetization and heat capacity measurements. Although a single phase with the cubic NaZn13-type structure (Fm3c) has been proved by the room temperature X-ray diffraction pattern, the phase transition has been clearly found to be a stepwise process in and curves under proper fields. Due to the strong competition between the FM order and AFM order, the characteristic is especially evident under low fields, weakens gradually with the increasing applied field and finally vanishes when the field is higher than 2 T. This multi-step magnetic transition results from the inhomogeneity of the sample, probably due to the inhomogeneous distribution of Nd atoms. [Copyright &y& Elsevier]

Abstract: Effect of Ti doping on the electrical transport and magnetic properties of layered Na0.8Co1−x Ti x O2 compounds has been investigated. The lattice parameters a and c increase with x. A minor amount of Ti doping results in a metal–insulator transition at low temperatures. For samples with x>0.03, the variable-range hopping process dominates the transport behavior above a certain temperature. The temperature dependence of magnetization of all the samples is found to obey the Curie–Weiss law. The mechanism of the doping effect is discussed. [Copyright &y& Elsevier]