TITLE

Response of magnetic nanoparticles to microwaves

AUTHOR(S)
Walton, Derek; Boehnel, Harald; Dunlop, David J.
PUB. DATE
November 2004
SOURCE
Applied Physics Letters;11/29/2004, Vol. 85 Issue 22, p5367
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Two important processes in ferromagnetic resonance are the first-order absorption of a photon and creation of a single magnon, and a second-order process in which the absorption of a photon results in the creation of two magnons of equal and opposite wave vector [M. Sparks, Ferromagnetic Relaxation (McGraw–Hill, New York, 1964)]. We have found that under resonance conditions for the second-order process, samples containing ∼0.1% magnetite absorb energy from the microwave field at the same rate as a solid magnetite sample. The resultant very high-energy density in the magnetic nanoparticles, coupled with a significant thermal energy barrier with the matrix, leads to a large temperature difference between the grains and their surroundings that makes it possible to magnetize and demagnetize the sample with a relatively small increase in sample temperature.
ACCESSION #
15244116

 

Related Articles

  • To the Calculation of Widths and Shifts of Microwave Spectral lines. Skvortsov, V. A. // Russian Physics Journal;Dec2003, Vol. 46 Issue 12, p1203 

    Within the framework of semiclassical collision theory, the method of rigorous calculation of widths and shifts of spectral lines is suggested that is not limited by the second order of perturbation theory and two-level approximation. Calculations are performed for spectral lines of a number of...

  • From zero resistance states to absolute negative conductivity in microwave irradiated two-dimensional electron systems. Iñarrea, J.; Platero, G. // Applied Physics Letters;7/31/2006, Vol. 89 Issue 5, p052109 

    Recent experimental results regarding a two-dimensional electron gas subjected to microwave radiation reveal that magnetoresistivity, apart from presenting oscillations and zero resistance states, can evolve to negative values at minima. Here the authors present a theoretical model which...

  • Observation of Zenneck-type waves in microwave propagation experiments. Ranfagni, A.; Fabeni, P.; Pazzi, G. P.; Ricci, A. M.; Trinci, R.; Mignani, R.; Ruggeri, R.; Cardone, F.; Agresti, A. // Journal of Applied Physics;7/15/2006, Vol. 100 Issue 2, p024910 

    The debated question of the superluminal speed of information remains open to different interpretations in spite of recent, apparently conclusive, contributions. A different point of view is here considered, which is based on experimental results of microwave propagation experiments, in...

  • LAND SURFACE MICROWAVE EMISSIVITIES OVER THE GLOBE FOR A DECADE. PRIGENT, CATHERINE; AIRES, FILIPE; ROSSOW, WILLIAM B. // Bulletin of the American Meteorological Society;Nov2007, Vol. 87 Issue 11, p1573 

    The article presents research into land surface microwave emissivities. A decade-long land surface emissivity dataset was calculated from Special Sensor Microwave Imager (SSM/I) satellite observations between 19 GHz and 85 GHz. Applications for land surface microwave emissivities include...

  • Microstructures and magnetostriction of two-phase Fe66-Pd30-Ni4 high-temperature ferromagnetic shape memory alloys. Lin, Yin-Chih; Lin, Chien-Feng; Yang, Jin-Bin; Lee, Hwa-Teng // Journal of Applied Physics;Apr2011, Vol. 109 Issue 7, p07A912 

    The microstructures and magnetostrictive strains of ferromagnetic shape memory Fe-Pd30 alloy systems with additions of Ni elements (4 at.%) have been investigated by a magnetostriction meter, scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM)....

  • Spin-torque-driven ferromagnetic resonance in point contacts. Staudacher, T.; Tsoi, M. // Journal of Applied Physics;Apr2011, Vol. 109 Issue 7, p07C912 

    We demonstrate the technique of spin-torque-driven ferromagnetic resonance (ST-FMR) in point contacts, which enables FMR studies in sample volumes as small as a few cubic nanometers. In our experiments, we use point contacts ∼10 nm in size to inject both dc and microwave currents into...

  • The Use of Operational Ice Charts for Evaluating Passive Microwave Ice Concentration Data. Agnew, Tom; Howell, Stephen // Atmosphere -- Ocean (Canadian Meteorological & Oceanographic Soc;Dec2003, Vol. 41 Issue 4, p317 

    More than 1380 regional Canadian weekly sea-ice charts for four Canadian regions and 839 hemispheric U.S. weekly sea-ice charts from 1979 to 1996 are compared with passive microwave sea-ice concentration estimates using the National Aeronautics and Space Administration (NASA) Team algorithm....

  • The reflection of an electromagnetic wave from the self-produced plasma. Mirzaie, M.; Shokri, B.; Rukhadze, A. A. // Physics of Plasmas;Jan2010, Vol. 17 Issue 1, p012104 

    The dynamic behavior of a high power microwave beam propagating through a gaseous medium, which is ionized in the wave field is investigated. By solving the wave equation, the reflection index of the produced plasma is obtained. It is shown that the cut off condition is different from that of...

  • Focusing by planoconcave lens using negative refraction. Vodo, P.; Parimi, P. V.; Lu, W. T.; Sridhar, S. // Applied Physics Letters;5/16/2005, Vol. 86 Issue 20, p201108 

    We demonstrate focusing of a plane microwave by a planoconcave lens fabricated from a photonic crystal having a negative refractive index and left-handed electromagnetic properties. An inverse experiment, in which a plane wave is produced from a source placed at the focal point of the lens, is...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics