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We report detailed investigations of the structure, magnetic properties, electronic transport, and specific heat in Mn-based antiperovskite compounds Mn3Cu0.5Zn0.5N. Most strikingly, there are several fascinating features: (i) The magnetoresistance at 30 kOe (40 kOe) exceeds ~1% (~2%) over a temperature span of ~70K (~25 K) from 5 to 140 K; (ii) magnetoresistance fluctuates at temperatures of 100-200 K, including an obvious sign reversal from negative to positive at ~140 K. Analysis of the specific heat reveals that the magnetoresistance reversal may originate from the reconstruction of the Fermi surface accompanying an antiferromagnetic-ferromagnetic transition. [ABSTRACT FROM AUTHOR]

The orthorhombic SrIrO3 perovskite was synthesized under 5 GPa and 1000 °C. It is paramagnetic below about 170 K and transfers to an unknown magnetism under higher temperature. A band type metal to insulator transition caused by a pseudogap was observed at about 44 K. Interestingly a positive magnetoresistance, i.e., resistance increased with applying magnetic field, was observed in the orthorhombic SrIrO3 perovskite below about 170 K. [ABSTRACT FROM AUTHOR]

Co-doped TiO2 nanofibers with an average diameter of ∼70 nm were fabricated with electrospinning method. X-ray diffraction measurements show that the nanofibers possess pure anatase structure. The obtained nanofibers exhibit evident room temperature ferromagnetism through magnetic measurement. The photoluminescence of the Co-doped TiO2 nanofibers is composed of two emission bands attributed to self-trapped excitons and oxygen vacancies, different from that of pure TiO2 nanofibers which only includes emission due to self-trapped excitons. Photoluminescence intensity due to oxygen vacancies vary with annealing atmosphere and Co concentration, and the ferromagnetic moment increases with the increment of oxygen vacancies. [ABSTRACT FROM AUTHOR]

Eu3+-doped TiO2 films were prepared on silicon substrates by sol-gel method. Anatase and rutile phases appear when the samples were heat treated in oxygen atmosphere at 500 and 900 °C, respectively. Photoluminescence (PL) properties were investigated under the excitation of 325 nm He–Cd laser. Visible PL peaking at 543, 598, 620, 665, and 694 nm are founded which are ascribed to 5D1→7F1, 5D0→7Fj(j=1,2,3,4) transitions of Eu3+ ions and the PL intensities reach maximum when the sample was heat treated at 700 °C. Compared with the PL spectra of pure TiO2, energy transfer from self-trapped exciton state to rare-earth ions is considered to exist in Eu3+-doped TiO2 system. After the sample was heat treated at higher temperatures than 700 °C, the PL intensity of Eu3+ ions decreases obviously, while near-infrared PL (815 nm) was detected which is due to the defect states associated with Ti3+ ions. Through the analysis of excitation and emission mechanism, we conclude that visible and near-infrared PLs are two competitive processes and energy back transfer from Eu3+ ions to TiO2 host is responsible for the decrease of visible PL intensity and the increase of near-infrared PL intensity. [ABSTRACT FROM AUTHOR]

Provides information on a study that presented the magnetic properties of iron/palladium multilayers prepared by ultrahigh vacuum electron-beam evaporation. Experimental procedure; Results and discussion.

The effect of the Cu interlayer on the exchange bias in FeMn/Cu/Co trilayers has been investigated. It is found that a thin interlayer can lower the strength of the exchange coupling between antiferromagnetic and ferromagnetic layers. The temperature dependencies of the left and right coercivities show an entirely different behavior, and they are very similar, when the Cu is thin, to those of a FeMn/Co bilayer with a very thin antiferromagnetic layer. With increasing the thickness of the Cu interlayer, the bias field decreases in most cases, but at low temperature it still remains large even when the Cu thickness is as thick as 1.8 nm. When the temperature is lower than 150 K, the dependence of the exchange bias on the Cu interlayer thickness exhibits a fluctuation behavior. This behavior disappears gradually with increasing temperature. [ABSTRACT FROM AUTHOR]

Tunneling giant magnetoresistance (MR) of the Fe-Al[sub 2]O[sub 3] nanogranular films has been observed over a wide range of Fe volume fraction x and it took a maximum of 4.4% at room temperature for the film with x=0.45 at H=10 kOe. Furthermore, the field dependence of MR of the samples is well described by the form proportional to the square of the magnetization. Moreover, an estimate of the magnetic anisotropy energy density K[sub u] increases with the decrease of x, yielding a value 2 orders of magnitude greater than the value for bulk Fe when x=0.23. The Bloch's law, M[sub S](T)=M[sub S0](1-BT[sup b]), can also hold for all the samples but with nonbulk parameters dependent on the Fe volume fraction. These results reveal a percolation effect on the magnetic properties, as well as the conductance, in such nanogranular films. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Focuses on a study on the effects of magnetoannealing on the giant magnetoresistance (GMR) in Fe[subx]Ag[100-x] granular films. Introduction to GMR effect in magnetic multilayers; Experimental procedures; Discussion on the change of GMR as a function of iron content in the as-sputtered silver-iron thin films.

Presents a study that investigated the causes of coercivity enhancement and the coercivity instability of acicular cobalt ferrite particles containing 0-9.2 wt percent Fe&sup2+; ions under the influence of magnetic field and temperature by means of transverse magnetic field annealing torque, and Mössbauer experiments. Methodology; Results of the study; Conclusions.

Presents studies on both the electronic and magnetic properties of LaCo[sub13] and La(Fe[subx]Al[sub1-x])sub[sub13] intermetallic compounds by cluster model calculations within the scheme of density-functional theory. Some properties of all the calculated clusters; Binding energy curves versus radial bond distance for cobalt, iron and aluminum and iron and aluminum clusters.

Presents information on a study that examined the effects of annealing on the properties of magnetic granular CoCu alloy ribbons that were prepared by the melt-spun method. Research method; Results and discussion.

Presents a study which discussed magnetism and microstructure of compositionally modulated disordered iron/tantalum films. Preparation of the multilayer films; Analysis of the series of samples.

Presents an abstract of the study 'Permanent Magnet Properties of Sputter-Deposited (FeCo)NdB Films,' by D. J. Sellmyer, Z. R. Zhao, Z. S. Shan and J. G. Zhao.