Download or read book Investigation of Magnetic Proximity Effect in Ferromagnet superconductor Thin Films by Low Temperature Magneto Optical Kerr Effect Measurement written by David A. Christiansen and published by . This book was released on 2012 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A room temperature Magneto Optical Kerr Effect (MOKE) experimental setup was expanded to improve performance and integrated with a liquid Helium cryogenic system. Ferromagnetic/superconductor hybrid systems have recently been intensively studied due to their interesting proximity effect and the possible applications such as a current switching device. Most of previous work focused on the superconducting property change due to the presence of the ferromagnet but not much research of the magnetic property change due to the superconducting transition has been done. Using the extended MOKE setup, magnetization from the top ferromagnetic layer can be measured below and above the critical temperature of the superconducting thin film layer. Temperatures as low as 4.2K were achieved and the magnetization with respect to applied magnetic field of a Permalloy/Niobium (Py/Nb) thin film was measured at 295K, 11K, and 4.2K. Coercivity increased as temperature decreased. A magnetization measurement with constant applied magnetic field was also performed with a temperature sweep passing the superconducting transition. However, due to temperature instability it was difficult to compare the magnetization above and below Tc of the Nb. Both hysteresis loops above and below the superconducting critical temperature were measured to be similar within the measurement error and have a coercivity of 160 ±16 Oe. Reasons for not detecting a magnetization change due to the superconductor could be either due to sample heating, thermometer calibration, the limited accuracy of measuring the coercivity in this sample, or the change due to the SC may be smaller or not exist.
Download or read book Construction of a Low Temperature Magneto optical Kerr Effect Set up and Applicatiom on Ferromagnetic Oxide Thin Films written by Nico Dix and published by . This book was released on 2006 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetische Materialien spielen in der heutigen Technik eine große Rolle. Seit der Entdeckung des Magnetismus sind viele Untersuchungsmethoden entwickelt worden. Wir haben eine Messapparatur zur Bestimmung von Magnetisierungskurven bei tiefen Temperaturen aufgebaut. Die Messungen können in einem Temperaturbereich von 10K bis 300K bei einem maximalen Magnetfeld von 0.8T durchgeführt werden. Um unsere Messapparatur zu testen haben wir die magnetischen Oxide Fe3O4 und SrRuO3 benutzt. Um das Auflösungsvermögen unseres Versuchsaufbaus zu erhöhen, haben wir die erste Variante von einer Ein-Detektor Methode mit Lock-In Verstärker zu einer Zwei-Detektor Differenzmethode umgebaut. Das maximale Auflösungsvermögen liegt bei 2mdeg. Weitere Untersuchungen wurden an SrRuO3 und La(0,67)Sr(0,33)MnO3 Dünnschichten durchgeführt. Es war dabei von besonderem Interesse die magnetischen Anisotripieeigenschaften zu bestimmen. Außerdem wurde das Wachstum von NiFe2O4 Dünnschichten untersucht. Zwei Serien wurden mittels einer RF-Sputter Anlage hergestellt. Hauptaugenmerk lag dabei auf der Analyse der Oberflächenstruktur.
Download or read book Proximity Effect in Ferromagnet superconductor Hybrid Systems written by Ion Cătălin Moraru and published by . This book was released on 2006 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of the Magneto optical Kerr Effect in Thin Multi layered Magnetic Films written by Lauren Chaykin and published by . This book was released on 2001 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Inverse Proximity Effect in Superconductor ferromagnet Bilayer Structures written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the polar Kerr effect using a zero-area-loop Sagnac magnetometer on Pb/Ni and Al/(Co-Pd) proximity-effect bilayers show unambiguous evidence for the 'inverse proximity effect, ' in which the ferromagnet (F) induces a finite magnetization in the superconducting (S) layer. To avoid probing the magnetic effects in the ferromagnet, the superconducting layer was prepared much thicker than the light's optical penetration depth. The sign and size of the effect, as well as its temperature dependence agree with recent predictions by Bergeret et al.[1].
Download or read book Ultrafast Magnetization Dynamics of SrRu03 Thin Films written by Matthew Clemens Langner and published by . This book was released on 2009 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1992 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1996 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proximity Effect in Superconductor ferromagnet Systems written by Jian Zhu and published by . This book was released on 2010 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proximity effect in superconductor (SC) - ferromagnet (FM) system produces many interesting phenomena due to the interplay between two competing orderings, superconductivity and ferromagnetism. This dissertation studies the influence of the orientation of magnetic moments on the superconducting transition temperature (Tc̳) in FM/SC/FM sandwiched structures. The superconducting transition temperature of a FM/SC/FM spin valve depends on the mutual orientation of the magnetic moments of the ferromagnetic layers. This phenomenon, called the spin switch effect, has been previously observed in FM/SC/FM systems as a Tc̳ difference between parallel and antiparallel configurations of the ferromagnetic layers. Both standard (TP̳c̳ TA̳P̳c̳) and inverse (TP̳c̳ TA̳P̳̳c̳) spin switch effects have been reported in different superconducting spin valve systems but the origin of the inverse spin switch effect was not understood. In this dissertation, a discovery of the coexistence of the standard and inverse spin switch effects in Ni1 Fe19 /Nb/Ni1 Fe19 /Ir25 Mn--5 spin valves is described. The measurements reveal that the inverse spin switch effect originates from dissipative flow of vortices induced by stray magnetic field of magnetostatically coupled Neel domain wall pairs in the ferromagnetic layers. This dissertation also studies the Tc̳ of FM/SC/FM sandwiched systems with noncollinear (neither parallel nor antiparallel) orientation of the magnetic moments of the ferromagnetic layers, where the odd triplet superconducting component is predicated to arise. Tc̳ in Cu48 Ni52 /Nb/Cu48 Ni52 trilayers as a function of the angle between the Cu48 Ni52 layer magnetizations is measured. The shape of the observed angular dependence ofTc̳ is in qualitative agreement with SC/FM proximity theories that account for the odd triplet component of the condensate, but large discrepancy in the magnitude is found.
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts Index written by and published by . This book was released on 1996 with total page 1634 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Local Imaging of Magnetic Flux in Superconducting Thin Films written by Tetyana Shapoval and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2011-04 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Local studies of vortex distribution in superconducting (SC) thin films and their pinning by natural and artificial defects were performed using low-temperature magnetic force microscopy (MFM). The depinning of vortices by the MFM tip was visualized and the local pinning force was estimated in a good agreement with global transport measurements. It was shown that the presence of an ordered array of ferromagnetic dots being in a magnetic vortex state underneath the SC film significantly influences the natural pinning landscape of the superconductor leading to commensurate pinning effects. This strong pinning exceeds the repulsive interaction between the SC vortices and allows vortex clusters to be located at each dot. For industrially applicable YBCO films the main question discussed was a correlation between vortices and artificial defects as well as vortex imaging on rough thin films. Since the surface roughness causes a severe problem to the scanning tip, a nanoscale wedge polishing technique was developed. Mounting the sample under a defined small angle results in a smooth surface and a monotonic thickness reduction of the film along the length of the sample.
Download or read book Magneto optical Kerr Effect Spectroscopy Study of Ferromagnetic Metal organic Heterostructures written by Wen Li and published by . This book was released on 2010 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Magnetic Thin Films and Magnetic Interfaces by Linear MOKE and Second Harmonic Generation written by Xiaojing Tan and published by . This book was released on 2009 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Johannis Davidis Hahnii oratio de usu venenorum in medicina written by and published by . This book was released on 1775 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ultrafast Magnetization Dynamics in the Presence of Strong Spin Orbit Coupling written by Colleen Kantner and published by . This book was released on 2010 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: The time-resolved magneto-optical Kerr effect is used to study magnetization dynamics in thin films of SrRuO3. This thesis focuses on two topics in particular: the influence of epitaxial strain on magnetization dynamics and magnetic orientation, and the origin of the dramatic slowing down of the demagnetization time near the Curie temperature. Magnetization dynamics in SrRuO3 are initiated by a temperature dependent rotation of the magnetocrystalline anisotropy field direction upon thermal excitation by the laser. The resulting dynamics depend on the orientation of the anisotropy field in the sample. We observe a change in the orientation as a function of epitaxially strain by looking at SrRuO3grown on various substrates with (001) orientation and distinct in-plane lattice parameters. We find that in SrRuO3 films under compressive strain, the anisotropy field moves in a plane perpendicular to the film surface. Beyond a certain degree of tensile strain, the anisotropy field moves in the plane parallel to the surface of the film. Support of this result from theoretical calculations and XRD measurements is discussed and attempts to strain tune films with a piezoelectric substrate are described. Near the Curie temperature, the demagnetization time in SrRuO3/SrTiO3(111) is found to increase by more than a factor of ten. Here, we study this effect in detail and derive an equation for the demagnetization time in terms of the spin flip time, starting from detailed balance and borrowing from a recent spin-based model for demagnetization[57, 58]. The demagnetization time is found to be proportional to the spin flip time and inversely proportional to the reduced temperature near Tc, allowing us to measure the spin flip time. We also relate the spin flip time and the damping parameter to the Curie temperature and find that the previously speculated upon relationship between the damping parameter in SrRuO3 and the anomalous Hall effect is strengthened.
Download or read book The Infrared Longitudinal Kerr Magneto optic Effect in Ferromagnetic Thin Films written by Stephen Barry Russell and published by . This book was released on 1962 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
