Sökning: "SQUID-magnetometry"

Visar resultat 1 - 5 av 21 avhandlingar innehållade ordet SQUID-magnetometry.

1. 1. Interacting Magnetic Nanosystems : An Experimental Study Of Superspin Glasses

   Författare :Mikael Svante Andersson; Roland Mathieu; Dino Fiorani; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spin glass; SQUID magnetometry; maghemite; magnetism; nanoparticles;

   Sammanfattning : This thesis presents experimental results on strongly interacting γ-Fe2O3 magnetic nanoparticles and their collective properties. The main findings are that very dense randomly packed (≈60%) γ-Fe2O3 nanoparticles form a replica of a spin glass. LÄS MER

3. 2. Tunable Magnetic Properties of Transition Metal Compounds

   Författare :Solveig Felton; Per Nordblad; Peter Svedlindh; John Chapman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic properties; Transition metal compounds; Magnetic structure; Domain structure; SQUID-magnetometry; MFM; Magnetism; Magnetism;

   Sammanfattning : The magnetic properties of transition metal compounds have been studied using SQUID-magnetometry, magnetic force microscopy and Lorentz transmission electron microscopy. New magnetic materials have been found and their magnetic properties have been determined. How the magnetic properties of a material can be changed through e.g. LÄS MER

4. 3. Frustrated magnetism in icosahedral structures : The influence of order-disorder in quasicrystals and approximant crystals

   Författare :Fernand Denoel; Roland Mathieu; Marc de Boissieu; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; quasicrystals; approximant crystals; spin glasses; SQUID magnetometry; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : This work will begin with an introduction to quasicrystals (QCs) and their structure, defining the unit cell-equivalent for icosahedral quasiperiodicity: a 3D tiling based on the golden ratio and aperiodic in all three dimensions. We briefly present the cut-and-project method used to generate QCs from a higher dimension hypercrystal, and how to build the 3D Penrose tilings, composed of the two golden rhombohedra. LÄS MER

5. 4. 3d Transition Metals Studied by Mössbauer Spectroscopy

   Författare :Saeed Kamali-Moghaddam; Roger Wäppling; Lennart Häggström; Friedrich Wagner; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Mössbauer Spectroscopy; SQUID Magnetometry; XRD; Layered Structures; Magnetism; Magnetic Superlattices; Nanoparticles; Li-ion Batteries; Brass; Fysik; Physics; Fysik;

   Sammanfattning : Layered crystals with magnetic elements as Co and Fe have been studied. In TlCo2Se2, where Co atoms in one sheet are separated by Tl and Se from the next Co sheet, magnetic interaction within and between the sheets have been studied. LÄS MER

7. 5. Carbon-based magnetic nanomaterials

   Författare :Valeria Zagaynova; Tatiana Makarova; Mauro Ricco; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon nanotube; fullerene; single molecular magnet; Mn12; graphite fluoride; nanoporous carbon; molecular magnetism; magnetic properties; SQUID magnetometry; x-ray diffraction; Raman spectroscopy; Materials Science; materialvetenskap;

   Sammanfattning : Magnetism of carbon-based materials is a challenging area for both fundamental research and possible applications. We present studies of low-dimensional carbon-based magnetic systems (fullerene-diluted molecular magnets, carbon nanotubes, graphite fluoride, and nanoporous carbon) by means of SQUID magnetometer, X-ray diffraction and vibrational spectroscopy, the latter techniques used as complementary instruments to find a correlation between the magnetic behaviour and the structure of the samples. LÄS MER