Synthesis, structural and magnetic properties of TM22+[MOIV(CN)(8)]center dot nH(2)O

Octacyanomolybdates (OCMs) TM2 divided by[Mo(CN)(8)]center dot nHO, where TM is Mn, Fe, Co, Ni, Cu were synthesised and characterised by IR spectroscopy and UV-VIS spectroscopy. The UV-VIS spectrum showed the intervalence charge transfer (IVCT) band between Mo-IV-CN-Cu-II and Mo-V-CN-Cu-I around 510 nm. Studied OCMs adopt tetragonal crystal structure. The H-1 NMR signals reflect the magnetic moment of the TM2- ions (mu(P)). The decay rates of free induction decay (FID) signals increase as pp and the applied static rf-field increases. The spin-lattice relaxation times at 27.7 MHz vary from 0.0187 ins (Mn) up to 0.45 ms (Cu). Magnetization measurements indicate long-range magnetic ordering of Mn- and Co- OCMs with the Curie temperature T-c = 4 K. The remaining OCMs (TM is Fe, Ni, Cu) are paramagnetic down to T = 1.9 K

More frequencies of KUV 02464+3239

Preliminary results on KUV 02464+3239, a pulsating DA white dwarf are presented. Located near the red edge of the DAV instability strip, KUV 02464+3239 shows large amplitude and long period pulsation modes. Up to now only one mode was known from a 50-minute-long light curve. Our more extended observations allowed the identification of three additional frequencies. The presence of previously known harmonics were confirmed and weak subharmonics are also noticeable at some parts of the light curve. This suggests the dominance of nonlinear pulsation effects from time to time.Comment: 3 pages, 3 eps figures; has been accepted for publication in Astronomische Nachrichten (Vol. 8, 2007), proceedings of the British-Hungarian-French N+N+N Workshop for Young Researcher

Technológiai Előretekintési Program

Az Országos Mûszaki Fejlesztési Bizottság döntése alapján 1998-ban átfogó elemzés kezdôdött Technoló- giai Elôretekintési Program (TEP) néven. A program célja, hogy a piaci és technológiai lehetôségek feltá- rásával hozzájáruljon a hosszú távú versenyképesség növeléséhez és ezen keresztül az életminôség javításá- hoz. A TEP a gazdasági, társadalmi folyamatok, a tudo- mány és technika eredményeinek elemzésével megje- löli azon kulcskérdéseket, döntési pontokat, amelyek meghatározzák az egyes szakmai területek illetve az ország jövôjét a következô 15-25 évben. Az Irányító Testület és a munkacsoportok elemezték a jelenlegi helyzetet, eltérô jövôképeket vázoltak fel, és a legked- vezôbbnek ítélt – de a mai feltételek mellett, tudatos, összehangolt erôfeszítések nélkül nem feltétlenül a leg- valószínûbb – jövôkép megvalósítását célzó ajánlásokat fogalmaztak meg. A legkedvezôbb jövôképbôl leve- zetett ajánlások tehát mindazoknak szólnak, akik köz- vetlenül vagy közvetve hatással lehetnek az egyes szakterületek vagy a magyar társadalom és gazdaság egészének jövôjére

Chemical Raman Enhancement of Organic Adsorbates on Metal Surfaces

Using a combination of first-principles theory and experiments, we provide a quantitative explanation for chemical contributions to surface-enhanced Raman spectroscopy for a well-studied organic molecule, benzene thiol, chemisorbed on planar Au(111) surfaces. With density functional theory calculations of the static Raman tensor, we demonstrate and quantify a strong mode-dependent modification of benzene thiol Raman spectra by Au substrates. Raman active modes with the largest enhancements result from stronger contributions from Au to their electron-vibron coupling, as quantified through a deformation potential, a well-defined property of each vibrational mode. A straightforward and general analysis is introduced that allows extraction of chemical enhancement from experiments for specific vibrational modes; measured values are in excellent agreement with our calculations.Comment: 5 pages, 4 figures and Supplementary material included as ancillary fil

Electrical activation and electron spin coherence of ultra low dose antimony implants in silicon

We implanted ultra low doses (2x10^11 cm-2) of 121Sb ions into isotopically enriched 28Si and find high degrees of electrical activation and low levels of dopant diffusion after rapid thermal annealing. Pulsed Electron Spin Resonance shows that spin echo decay is sensitive to the dopant depths, and the interface quality. At 5.2 K, a spin decoherence time, T2, of 0.3 ms is found for profiles peaking 50 nm below a Si/SiO2 interface, increasing to 0.75 ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum information is encoded in donor electron spins

H-1 NMR on (NixMn1-x)(3)[Cr(Cn)(6)](2) center dot NH(2)O

We report on H-1 NMR of (NixMn1-x)(3)[Cr(Cn)(6)](2) center dot nH(2)O hexacyanochromates, where x changes from 0 to 1. The decay time constants of the free induction decay signals described by an effective spin-spin relaxation time T-2eff obtained from M(t) = M-0 exp(t/T-2eff) decrease as the local magnetic moments increase produced by the magnetic transition metal ions at the sites of the resonant H-1 nuclei. The recovery of the magnetization in the spin-lattice relaxation time (T-1) experiments was single-exponential

Electrical activation and electron spin resonance measurements of implanted bismuth in isotopically enriched silicon-28

We have performed continuous wave and pulsed electron spin resonance measurements of implanted bismuth donors in isotopically enriched silicon-28. Donors are electrically activated via thermal annealing with minimal diffusion. Damage from bismuth ion implantation is repaired during thermal annealing as evidenced by narrow spin resonance linewidths (B_pp=12uT and long spin coherence times T_2=0.7ms, at temperature T=8K). The results qualify ion implanted bismuth as a promising candidate for spin qubit integration in silicon.Comment: 4 pages, 4 figure

Spin-Dependent Scattering off Neutral Antimony Donors in 28-Si Field-Effect Transistors

We report measurements of spin-dependent scattering of conduction electrons by neutral donors in an accumulation-mode field-effect transistor formed in isotopically enriched silicon. Spin-dependent scattering was detected using electrically detected magnetic resonance where the spectra show resonant changes in the source-drain voltage for conduction electrons and electrons bound to donors. We discuss the utilization of spin-dependent scattering as a mechanism for the readout of donor spin-states in silicon based quantum computers.Comment: 14 pages, 3 figures. Correction made to figure3(b