Скачкообразные квантовые фазовые переходы в вихревой системе и динамическая комплексная магнитная проницаемость двойниковых YBa-=SUB=-2-=/SUB=-Cu-=SUB=-3-=/SUB=-O-=SUB=-7-x-=/SUB=- высокотемпературных сверхпроводников

A nonlocal high-frequency method for measuring the dynamic complex magnetic permeability with enhanced spatial resolution is developed to simultaneously determine the bulk and local character of stepwise penetration of a magnetic flux through twin boundaries (TBs) into a YBa2Cu3O7-x HTSC sample during its stepwise decomposition into twins. By the values of fields corresponding to the regions of steps, the thermodynamic first critical magnetic fields are determined: the penetration of a flux into a sample – a Josephson medium; the development of a critical state in the Josephson medium; the penetration of a flux into twins; and the values of the critical fields of phase transitions in the vortex system of the HTSC sample, such as the melting fields of a vortex crystal, the formation of a superconducting glass state in the sample, and the transition to the vortex glass and Bragg glass states.

Decomposition of fluorophosphoryl diazide: a joint experimental and theoretical study

The stepwise decomposition of fluorophosphoryl diazide (FP(O)(N3)2), via nitrene (FP(O)(N3)N) and the cyclic intermediate (FP(O)N2), was experimentally and theoretically studied.

Synthesis, Crystal Structures, and Spectroscopic and Thermal Properties of New Cobalt Thiocyanato Coordination Compounds Based on 3-Methylpyridine as a Neutral Coligand

Reaction of cobalt(II) thiocyanate with 3-methylpyridine in water leads to the formation of the new ligand-rich cobalt(II) thiocyanato coordination compounds [bis(thiocyanato-N)-tetrakis(3-methylpyridine- N)cobalt(II)] (1) and [bis(thiocyanato-N)-bis(3-methylpyridine-N)-diaqua-cobalt(II)] (2). The crystal structures of 1 and 2 consist of discrete complexes in which the cobalt(II) cations are coordinated by two terminally N-bonded thiocyanato anions and four or two terminally bonded coligands, respectively, in a slightly distorted octahedral geometry. Investigations on the thermal degradation behavior of 1 and 2 using simultaneous differential thermoanalysis and thermogravimetry as well as X-ray powder diffraction and IR spectroscopy have proven that on heating a stepwise decomposition takes place, which leads to the formation of the new phase-pure ligand-deficient intermediate [bis(thiocyanato-N)-bis(3-methylpyridine-N)cobalt(II)] (3). The crystal structure of 3 also consists of discrete complexes, but the cobalt(II) cations are only tetrahedrally coordinated by two terminally N-bonded thiocyanato anions and two terminally bonded coligands. The structures and the thermal properties are discussed and compared with that of related transition metal thiocyanato coordination compounds.