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Title: Nanocrystalline zinc ferrite films studied by magneto-optical spectroscopy

Ferrimagnetic Zn-ferrite (ZnFe{sub 2}O{sub 4}) films can be grown with the ferromagnetic resonance linewidth of 40 Oe at 9.5 GHz without going through a high temperature processing. This presents interest for applications. The work deals with laser ablated ZnFe{sub 2}O{sub 4} films deposited at O{sub 2} pressure of 0.16 mbar onto fused quartz substrates. The films about 120 nm thick are nanocrystalline and their spontaneous magnetization, 4πM{sub s}, depends on the nanograin size, which is controlled by the substrate temperature (T{sub s}). At T{sub s} ≈ 350 °C, where the grain distribution peaks around ∼20–30 nm, the room temperature 4πM{sub s} reaches a maximum of ∼2.3 kG. The films were studied by magnetooptical polar Kerr effect (MOKE) spectroscopy at photon energies between 1 and 5 eV. The complementary characteristics were provided by spectral ellipsometry (SE). Both the SE and MOKE spectra confirmed ferrimagnetic ordering. The structural details correspond to those observed in MgFe{sub 2}O{sub 4} and Li{sub 0.5}Fe{sub 2.5}O{sub 4} spinels. SE experiments confirm the insulator behavior. The films display MOKE amplitudes somewhat reduced with respect to those in Li{sub 0.5}Fe{sub 2.5}O{sub 4} and MgFe{sub 2}O{sub 4} due to a lower degree of spinel inversion and nanocrystalline structure. The results indicate that the films are free of oxygen vacancies andmore » Fe{sup 3+}-Fe{sup 2+} exchange.« less
Authors:
;  [1] ; ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague (Czech Republic)
  2. Nanotechnology Center, VŠB-Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba (Czech Republic)
  3. Department of Physics, Central University of Kerala, Kasaragod, Kerala 671314 (India)
  4. Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)
  5. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)
  6. Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa (Japan)
  7. Groupe d'Etude de la Matière Condensée (GEMaC), CNRS-UVSQ, 45 Avenue des Etats-Unis, 78935 Versailles (France)
Publication Date:
OSTI Identifier:
22409979
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTALS; ELLIPSOMETRY; EV RANGE; FERRIMAGNETIC MATERIALS; FERRIMAGNETISM; FERRITES; FERROMAGNETIC RESONANCE; FILMS; GHZ RANGE; IRON IONS; KERR EFFECT; LASER RADIATION; MAGNESIUM COMPOUNDS; MAGNETIZATION; NANOSTRUCTURES; QUARTZ; SPINELS; SUBSTRATES; VACANCIES