Raman spectra of monoclinic hafnium oxide HfO2 were measured at temperatures up to 1100 K. Raman peak shifts and broadenings are reported. Phonon dynamics calculations were performed with the shell model to obtain the total and partial phonon density of states, and to identify the individual motions of Hf and O atoms in the Raman modes. Correlating these motions to the thermal peak shifts and b...

a mathematical model of sorption of zirconium and hafnium cations mixture and elution of these ions from a cation exchange resin bed is developed. sulfuric acid is selected as the eluent for selective separation of zr and hf in a packed bed of dowex cation exchange resin. the column model is a dispersed plug flow model,and assumed to consist of randomly packed synthetic and spherical resin bead...

Uniform period sub-micron gratings have been fabricated using focused ion beam milling on hafnium oxide waveguides. Atomic force microscopy indicates that the gratings have smooth and uniform profiles. At the period of 330 nm, the largest peak-to-peak height that was achieved was 85 nm. Scattering at the grating imperfections was found to be at least two orders of magnitude weaker than the inte...

Let H(S) be the Hardy space on the unit sphere S in C, n ≥ 2. Consider the Hankel operator Hf = (1 − P )Mf |H(S), where the symbol function f is allowed to be arbitrary in L(S, dσ). We show that for p > 2n, Hf is in the Schatten class Cp if and only if f − Pf belongs to the Besov space Bp. To be more precise, the “if” part of this statement is easy. The main result of the paper is the “only if ...

The Minnesota Nano Center’s Keller Hall facility includes an atomic layer deposition (ALD) machine that is capable of depositing uniform alumina (Al2O3), hafnium oxide (HfO2), silicon dioxide (SiO2), zinc oxide (ZnO), and titanium dioxide (TiO2). ALD works by building alternate layers on a film using two different precursor gases – one usually supplying the metallic atoms and water vapor (H2O) ...

Defect states in different dielectric materials with crystalline and amorphous structures were investigated with two models, the Broer model and the Bloch model. For crystalline structures as in hafnium oxide, defects were found to fit well with the Broer model due to strong local magnetic-field-orientation dependency. In amorphous materials, for example, organosilicate glass, defects were foun...