Search

In this paper, magnetic and dielectric properties of the quasi-two-dimensional triangular-lattice system CuCrS2 and its B-site-diluted analogs CuAl1−xCrxS2 (x = 0.01 and x = 0.02) are investigated. Antiferromagnetic phase transition is observed at about 38.5 K by magnetization measurement without shift induced by a small amount of doping Al. Magnetodielectric effect is found near TN in each of the three compounds. The dielectric constant decreases and the magnetocapacitance increases with the increase of substitution of nonmagnetic Al3+ ions for the magnetic Cr3+ ions. The negative magnetocapacitive effect reaches ~ 13% for CuAl0.02Cr0.98S2.

Ternary yttrium chromium sulfide, Y2CrS4, prepared by the solid-state reaction of Y2S3, Cr, and S, was found to exhibit an antiferromagnetic transition at about 64 K. The X-ray diffraction pattern at 300 K was refined with space group Pca21, and the structure parameters were determined to be a = 12.51 A, b = 7.53 A, and c = 12.49 A. We investigated the magnetotransport properties, and observed negative colossal magnetoresistance reaching up to 2.5 × 104% in the semiconducting compound of Y2CrS4.

Here we provide the material design of a possible high temperature multiband superconductor (HTMS) made of a 'heterostructure at the atomic limit' formed by alternate layers of electron doped FeAs and CuO2 separated by intercalated NdO spacers. This new class of materials is derived from the two well known electron doped superconductors Nd2CuO4 and NdOFeAs belonging to the cuprate and the pnictide families, respectively. The calculated local electronic density of states show that both the Cu and Fe bands cross the Fermi surface. This will provide (i) superconducting Fermi arcs made by charges from the CuO2 plane, and (ii) tubular Fermi surfaces, as in pnictides, by itinerant charges from the Fe atomic layer. The electronic properties of this new class of materials are presented to highlight the possibility of material design of a HTMS tuned at a shape resonance in the energy gap parameters belonging to the class of Fano–Feshbach resonances called superstripes. The Nd L3-edge x-ray absorption near edge structure (XANES) of the proposed model system is calculated and compared with the XANES spectra of the Nd2CuO4 and NdOFeAs parent compounds.

We use the transfer-matrix method to research the band structures in one-dimensional photonic crystals composed of anomalous dispersion material (saturated atomic cesium vapor). Our calculations show that that type of photonic crystal possesses an ultra-narrow photonic band gap and this band gap is tunable when altering the electron population in the atomic ground state of the anomalous dispersion material by the optical pumping method.