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Title: Structural and magnetic resonance investigations of CuCr{sub 2}S{sub 4} nanoclusters and nanocrystals

Nanoclusters and nanocrystals of the room temperature magnetic spinel CuCr{sub 2}S{sub 4} synthesized using a facile solution-based method have been examined by transmission electron microscopy, magnetic measurements, and magnetic resonance over a wide frequency range 9.6–80 GHz and at temperatures down to 4.2 K. Decreasing of the resonance field and broadening of the resonance lines below 50 K for both samples are due to the freezing of magnetic moments of nanocubes and nanocrystalline particles constituting nanoclusters. The effective fields of averaged magnetic anisotropy 〈H{sub A}〉≅ 2.4 kOe are similar for both nanopowder samples as estimated from resonance measurements at T = 4.2 K. An additional blocking temperature T{sub b} ≅ 300 K appears in nanoclusters due to freezing of the magnetic moment of the entire cluster as a whole. Below this blocking temperature, the magnetic dipolar field acting in boundary areas of interacting constituent nanocrystals is responsible for the additional low-field resonance line observed in the resonance spectra of nanoclusters at X-band.
Authors:
; ;  [1] ;  [2] ; ; ;  [1] ;  [3] ; ;  [4]
  1. Kirensky Institute of Physics, SB RAS, Akademgorodok, Krasnoyarsk 660036 (Russian Federation)
  2. (Russian Federation)
  3. Siberian Federal University, 79 Svobodny prosp., Krasnoyarsk 660041 (Russian Federation)
  4. MINT Center, The University of Alabama, Tuscaloosa, Alabama 35487 (United States)
Publication Date:
OSTI Identifier:
22314563
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 5; Other Information: (c) 2014 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; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CHANNELING; FREEZING; GHZ RANGE; MAGNETIC MOMENTS; MAGNETIC RESONANCE; MATHEMATICAL SOLUTIONS; NANOSTRUCTURES; POTASSIUM 50; POWDERS; SPINELS; TEMPERATURE RANGE 0273-0400 K; TRANSMISSION ELECTRON MICROSCOPY