A stable and reproducible superconductivity transition between 80 and 93 K has been unambiguously observed both resistively and magnetically in a new Y-Ba-Cu-O compound system at ambient pressure. An estimated upper critical field H c2(0) between 80 and 180 T was obtained.

https://link.aps.org/pdf/10.1103/PhysRevLett.58.908

Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressure

Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm complementary metal–oxide–semiconductor (CMOS) technology. A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are (a) permittivity, band gap, and band alignment to silicon, (b) thermodynamic stability, (c) film morphology, (d) interface quality, (e) compatibility with the current or expected materials to be used in processing for CMOS devices, (f) process compatibility, and (g) reliability. Many dielectrics appear favorable in some of these areas, but very few materials are promising with respect to all of these guidelines. A review of current work and literature in the area of alternate gate dielectrics is given. Based on reported results and fundamental considerations, the pseudobinary materials systems offer large flexibility and show the most promise toward success...

/pdf/high-k-gate-dielectrics-current-status-and-materials-zjvba0c4u8.pdf

High-κ gate dielectrics: Current status and materials properties considerations

The oxide superconductors, particularly those recently discovered that are based on La2CuO4have a set of peculiarities that suggest a common, unique mechanism: they tend in every case to occur near a metal-insulator transition into an odd-electron insulator with peculiar magnetic properties. This insulating phase is proposed to be the long-sought “resonating-valence-bond” state or “quantum spin liquid” hypothesized in 1973. This insulating magnetic phase is favored by low spin, low dimensionality, and magnetic frustration. The preexisting magnetic singlet pairs of the insulating state become charged superconducting pairs when the insulator is doped sufficiently strongly. The mechanism for superconductivity is hence predominantly electronic and magnetic, although weak phonon interactions may favor the state. Many unusual properties are predicted, especially of the insulating state.

http://science.sciencemag.org/content/sci/235/4793/1196.full.pdf

The resonating valence bond state in La2CuO4 and superconductivity

A negative isotropic magnetoresistance effect more than three orders of magnitude larger than the typical giant magnetoresistance of some superlattice films has been observed in thin oxide films of perovskite-like La0.67Ca0.33MnOx. Epitaxial films that are grown on LaAIO3 substrates by laser ablation and suitably heat treated exhibit magnetoresistance values as high as 127,000 percent near 77 kelvin and ∼1300 percent near room temperature. Such a phenomenon could be useful for various magnetic and electric device applications if the observed effects of material processing are optimized. Possible mechanisms for the observed effect are discussed.

http://science.sciencemag.org/content/sci/264/5157/413.full.pdf

Thousandfold Change in Resistivity in Magnetoresistive La-Ca-Mn-O Films

In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

We have systematically studied the composition dependence of the dielectric properties of Zr1-xAlxO2-x/2 and Zr1-xSixO2. An essentially linear variation of the static dielectric constant, es, was observed as a function of composition, x, for compositions rich in the p-block element, i.e., x > 0.4, for both chemical systems. However an abrupt change in es is found near x ≈ 0.35, associated with the onset of crystallinity in as-deposited films. Breakdown fields do not show a comparable composition dependence. Measurements of the index of refraction at optical frequencies, combined with a simple Clausius–Mossotti interpretation, indicates that low-frequency (ionic) contributions to the polarizability exhibit systematic deviation with respect to values linearly interpolated from the endmembers. These trends are not consistently affected by the presence of crystalline order, but are related to changes associated with heterogeneous local oxygen coordination and bonding.

https://www.worldscientific.com/doi/pdf/10.1142/S2010135X15500101

Dielectric properties of amorphous Zr–Al–O and Zr-Si-O thin films

La6BaYCu8O20: A New Oxygen Deficient Perovskite

We have fabricated and studied thin films of VO 2 and lamellar VO 2 /Au metamaterials. Optical properties of VO 2 /Au metamaterials are consistent with the transition between hyperbolic and metallic phases occurring at elevated temperatures.

/pdf/tunable-vo2-au-hyperbolic-metamaterial-2msa16jhsi.pdf

Tunable VO2/Au hyperbolic metamaterial

https://pure.rug.nl/ws/files/14553896/1993JSolidStateChemHessen.PDF

R. B. van Dover

Papers

Dielectric properties of amorphous Zr–Al–O and Zr-Si-O thin films

La6BaYCu8O20: A New Oxygen Deficient Perovskite

Tunable VO2/Au hyperbolic metamaterial

A reduced neodymium titanate with a new intergrowth structure type

Summary Abstract: Low temperature deposition and properties of superconducting NbN by reactive dc magnetron sputtering