A5066704308- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Magnetic Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Metallic Glasses and Amorphous Alloys
- Magnetic Properties of Alloys
- Force Microscopy Techniques and Applications
- Magnetic Field Sensors Techniques
- Electronic and Structural Properties of Oxides
- Rare-earth and actinide compounds
- Theoretical and Computational Physics
- ZnO doping and properties
- Diamond and Carbon-based Materials Research
- Iron-based superconductors research
- Characterization and Applications of Magnetic Nanoparticles
- Mechanical and Optical Resonators
- Magneto-Optical Properties and Applications
- Copper Interconnects and Reliability
- Superconductivity in MgB2 and Alloys
- Heusler alloys: electronic and magnetic properties
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Semiconductor materials and devices
- Quantum and electron transport phenomena
University of Nebraska–Lincoln
2016-2025
National Taiwan University of Science and Technology
2024
Manufacturing Advocacy & Growth Network (United States)
2022
San Francisco State University
2005
National Tsing Hua University
2004
Netherlands Institute for Radio Astronomy
1999
National Institute of Standards and Technology
1996
Oak Ridge National Laboratory
1996
Brookhaven National Laboratory
1993
AT&T (United States)
1987-1989
Magnetoresistive (MR) sensors have been identified as promising candidates for the development of high-performance magnetometers due to their high sensitivity, low cost, power consumption, and small size. The rapid advance MR sensor technology has opened up a variety applications. These applications are in different areas that require with properties. Future each these requires an overview strategic guide. An roadmap (non-recording applications) was therefore developed made public by...
Measurements of the transport critical-current density (Jc), magnetization Jc, and magnetoresistance in a number bulk sintered samples Y1Ba2Cu3Ox from several different laboratories indicate that Jc is limited by weak-link regions between high regions. The has Josephson character, decreasing two orders magnitude as magnetic field increased 0.1 to 10 mT at 77 K. An examination grain-boundary region shows no observable impurities or second phases scale [001] lattice planes (∼12 Å). effect...
Recently, it has been argued that a strong electron-phonon interaction arising from the Jahn-Teller splitting of outer Mn $d$ level plays crucial role in understanding nonmetal-to-metal transition observed ${\mathrm{La}}_{1\ensuremath{-}x}{A}_{x}\mathrm{Mn}{\mathrm{O}}_{3}(A=\mathrm{C}\mathrm{a},\phantom{\rule{0ex}{0ex}}\mathrm{S}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{B}\mathrm{a})$ system. We show, by neutron powder diffraction,...
Superconducting ${\mathrm{Y}}_{1}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}x}$ films were produced by metal molecular-beam epitaxy with one electron beam and two thermal cells a molecular oxygen-gas source. The epitaxially grown on SrTi${\mathrm{O}}_{3}$(100) an $a$-axis orientation perpendicular to the plane, $b$ $c$ axes ordered in plane. A sharp resistive superconducting transition ${T}_{c}(R=0)$ at 82 K was obtained. lower limit of average ${J}_{c}$ plane is...
We have prepared superconducting thin films of Y-Ba-Cu-O with Tc onsets above 95 K by both diode and magnetron sputtering. Films full superconductivity (R=0) at 85 been produced dc The compositions the are fairly uniform across an area 50 mm in diameter through film thickness. Structural properties were studied x-ray diffraction. Critical current densities range 3000 to 104 A/cm2 measured 4.2 K.
Double-slit diffraction is a corner stone of quantum mechanics. It illustrates key features mechanics: interference and the particle-wave duality matter. In 1965, Richard Feynman presented thought experiment to show these features. Here we demonstrate full realization his famous experiment. By placing movable mask in front double-slit control transmission through individual slits, probability distributions for single- arrangements were observed. Also, by recording single electron detection...
Nitrogen-vacancy (NV) magnetometry offers an alternative tool to detect paramagnetic centers in cells with a favorable combination of magnetic sensitivity and spatial resolution. Here, we employ NV relaxometry cytochrome C (Cyt-C) nanoclusters. Cyt-C is water-soluble protein that plays vital role the electron transport chain mitochondria. Under ambient conditions, heme group remains Fe3+ state, which paramagnetic. We vary concentration from 6 54 μM observe reduction spin–lattice relaxation...
We have investigated the surface chemical composition of crystalline films ${\mathrm{La}}_{0.65}{\mathrm{Sr}}_{0.35}{\mathrm{MnO}}_{3}$ by angle-resolved x-ray photoelectron spectroscopy. The was found to be significantly different from that bulk because an appreciable Sr segregation. Furthermore, our study suggests this segregation has caused a major restructuring region characterized formation Ruddlesden-Popper phase...
We present femtosecond time-resolved measurements on the high-${\mathit{T}}_{\mathit{c}}$ superconductor ${\mathrm{Tl}}_{2}$${\mathrm{Ba}}_{2}$${\mathrm{Ca}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{10}$. At temperatures below ${\mathit{T}}_{\mathit{c}}$, we observe a relaxation process which is distinct from equilibration of hot carriers in normal state. Our results demonstrate an increasing rate as superconducting gap opens. This consistent with behavior conventional metallic superconductors.
A new technique for producing thin films of the high-temperature perovskite superconductors, LnBa2Cu3O7−x, where Ln represents a rare-earth element, using spin-on metalorganic precursors is described. Pyrolysis spin-coated films, consisting mixed metal (2-ethyl hexanoates), leads to black up several microns thick whose degree orientation function processing temperature and duration. Representative YBa2Cu3O7−x on MgO begin exhibit with c axis perpendicular film plane at heat treatments above...
[Fe(Htrz)2(trz)](BF4) (Fe-triazole) spin crossover molecules show thermal, electrical, and optical switching between high (HS) low (LS) states, making them promising candidates for molecular spintronics. The LS HS transitions originate from the electronic configurations of Fe(II) are considered to be diamagnetic paramagnetic, respectively. state has six paired electrons in ground states with no interaction magnetic field a behavior is usually observed. While bulk properties Fe-triazole...
Nanocomposite FePt:SiO2 thin films consisting of high anisotropy FePt particles embedded in a SiO2 matrix have been successfully fabricated by annealing the as-deposited FePt/SiO2 multilayers. By adjusting temperatures and compositions, were obtained with coercivity 3.8 kOe grain size 10 nm, which are suitable for high-density magnetic recording. Magnetic activation volumes measured thermal stability is discussed.
Angle-resolved core-level photoemission has been utilized to study the surfaces of crystalline thin films manganite ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ ($x=0.1$ and 0.35). It is found that both surface termination Ca concentration depend on bulk concentration. For ${\mathrm{La}}_{0.65}{\mathrm{Ca}}_{0.35}{\mathrm{MnO}}_{3},$ terminal layer predominately Mn-O, while for ${\mathrm{La}}_{0.9}{\mathrm{Ca}}_{0.1}{\mathrm{MnO}}_{3},$ majority La/Ca-O terminated....
A noneptaxially grown double-layered thin-film medium of nanocompsite FePt:C with a FeCoNi soft underlayer for high-density perpendicular magnetic recording was fabricated and investigated. Square-shaped loops remanance ratio nearly equal to one coercivity as large 8.5 kOe were obtained this ordered medium. The formation the L10 phase is confirmed by electron diffraction experiments. Transmission microscope observations reveal that FePt grains uniform size less than 5 nm are embedded in C...
High-density recording media require materials with a high magnetization and coercivity as well chemical stability, wear, corrosion resistance. We explore the potential of granular metal films for media. Films Fe granules about 150 Å in size embedded an amorphous SiO2 matrix exhibit coercivities 3 kOe at low temperatures 1.1 room temperature, magnetizations emu/g. The methods which these are fabricated, essential microstructure characterization, magnetic measurements described.
Current-voltage tunneling characteristics in a high-critical-temperature superconducting material containing predominately ${\mathrm{Y}}_{1}$${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{9\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ have been measured using the break-junction technique. Sharp gap structure was observed, with largest superconductive energy to be \ensuremath{\Delta}=19.5\ifmmode\pm\else\textpm\fi{}1 meV, assuming superconductor-insulator-superconductor...
We have utilized an iodine absorption cell to enable detailed Raman studies at low frequency (down 15 ${\mathrm{cm}}^{\ensuremath{-}1}$) in a thin film of the high-temperature superconductor ${\mathrm{Ba}}_{2}$Y${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$. Subtraction spectra just above and well into superconducting phase reveals weak broad feature (maximum near 400 ${\mathrm{cm}}^{\ensuremath{-}1}$, half width maximum approximately 250 ${\mathrm{cm}}^{\ensuremath{-}1}$), which we tentatively...
Superparamagnetic iron oxide nanoparticles (SPIONs) are widely investigated and utilized as magnetic resonance imaging (MRI) contrast therapy agents due to their large moments. Local field inhomogeneities caused by these high moments used generate T2 in clinical high-field MRI, resulting signal loss (darker contrast). Here we present strong T1 enhancement (brighter contrast) from SPIONs (diameters 11 nm 22 nm) observed the ultra-low (ULF) MRI at 0.13 mT. We have achieved a longitudinal...
The issues of sign reversal the Hall voltage and scaling between longitudinal (${\mathrm{\ensuremath{\rho}}}_{\mathit{x}\mathit{x}}$) (${\mathrm{\ensuremath{\rho}}}_{\mathit{x}\mathit{y}}$) resistivities are studied in ${\mathrm{Tl}}_{2}$${\mathrm{Ba}}_{2}$${\mathrm{Ca}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{10}$ films which vortex dynamics is drastically changed by flux pinning at heavy-ion-irradiation--induced linear defects. While anomaly diminishes with increasing defect concentration,...
In this study, we showed that a magnetic coercivity (Hc) as high 37 kOe was obtained in CoPt thin film contains separated nanometer-size crystallites. We prepared films with thicknesses of 5 and 175 nm by magnetron sputtering. After annealing an Ar/H2 atmosphere at temperatures from 650 to 750 °C for 3–12 h, measured the properties found Hc relates temperature, time thickness. From atomic force microscopy studies, single domain size is range 100–200 nm. The likely due well-separated...
Periodic magnetic nanodot arrays have been produced on an area as large 1 cm×1 cm by direct nanolithography using interferometric laser radiation. The dots are formed the local annealing of sputtered amorphous Co–C films in regions where intensity is highest. At room temperature exhibit ferromagnetic order and embedded a paramagnetic matrix. onset room-temperature ferromagnetism caused nanoscale chemical morphological changes during dot formation reflects phase separation Co-rich clusters....
We have studied the effect of visible and near-infrared light on electrical properties superconducting thin films YBa2Cu3O7−δ. The responses we observe can all be explained in terms heating film to a temperature above transition. No evidence that directly affects superconductivity was found.
FexTi100−x alloys over a wide composition range has been made by high-rate sputtering and studied 57Fe Mössbauer spectroscopy. Samples with 30≤x≤80 are amorphous whereas samples x≥85 metastable crystalline bcc alloys. Large differences in magnetic properties (e.g., TC) hyperfine interactions (Heff, isomer shift) found between the Comparison of FeTi Fe2Ti states show that short-range order state no resemblence to compounds.
We demonstrate a simple low-power, magnetic sensor system suitable for high-sensitivity magnetic-field mapping, based on solid-state tunnel junction devices with minimum detectable fields in 100 pT range at room temperature. In this paper, we discuss method that uses multilayer thin films to improve the performance of soft ferromagnetic layer magnetoresistive applications, by reducing coercivity and/or improving reversibility. have used it design our new sensor. This has sensitivity as high...
Recently, broken symmetry effect induced edge states in two-dimensional electronic systems have attracted great attention. However, whether may exist strongly correlated oxides is not yet known. In this work, using perovskite manganites as prototype systems, we demonstrate that do oxides. Distinct appearance of ferromagnetic metallic phase observed along the manganite strips by magnetic force microscopy. The strong influence on transport properties strips, leading to higher metal–insulator...