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Title: Coexistence of considerable inter-particle interactions and spin-glass behavior in La{sub 0.7}Ca{sub 0.3}MnO{sub 3} nanoparticles

We have studied the magnetic and spin-glass (SG) properties of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} single-crystalline nanoparticles, which were prepared by the mechanical milling method with different milling times (t{sub m}). Analyzing the susceptibility data in the paramagnetic region indicates both ferromagnetic (FM) and anti-FM interactions coexisting in nanoparticles. Additionally, there is a peak associated with the freezing temperature (T{sub f}) appearing on the real part curve of the ac susceptibility, χ′(T). The T{sub f} value increases with increasing frequency as expected for SG systems. The SG behavior was also checked by using the criterion parameter c = ΔT{sub f}/T{sub f}Δ(log{sub 10}f), and the power law τ = τ{sub 0}(T/T{sub g} − 1){sup −zν}. The obtained values of c ≈ 5 × 10{sup −2}, τ{sub 0} ≈ 10{sup −5} s and zν ≈ 2–3 are consistent with those expected for SG-like systems, suggesting an existence of a SG phase transition at T{sub g} below T{sub f}, which decreases with decreasing 〈D〉. Basing on ln(f) versus T{sub f} data, and the Néel-Arrhenius model [ln(f) = ln(f{sub 0}) - E{sub a}/k{sub B}T] and Vogel–Fulcher law [ln(f) = ln(f{sub 0}) - E{sub a}/k{sub B}(T - T{sub 0})], the Larmor frequency (f{sub 0}), activation energy (E{sub a}) and effective temperature (T{sub 0}) for the samples with differentmore » 〈D〉 were determined. Obtained results indicate the existence a strong interaction between nanoparticles.« less
Authors:
 [1] ;  [2] ; ;  [3] ; ;  [1] ;  [4] ;  [5]
  1. Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)
  2. (Viet Nam)
  3. Institute of Materials Science, VAST, 18-Hoang Quoc Viet, Hanoi (Viet Nam)
  4. Nha Trang Pedagogic College, 1 Nguyen Chanh Street, Nha Trang (Viet Nam)
  5. Department of Physics, University of Vinh, Nghe An (Viet Nam)
Publication Date:
OSTI Identifier:
22273897
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; 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; ACTIVATION ENERGY; CALCIUM COMPOUNDS; FREEZING; FREQUENCY DEPENDENCE; LANTHANUM COMPOUNDS; MAGNETIC SUSCEPTIBILITY; MANGANATES; MILLING; MONOCRYSTALS; NANOSTRUCTURES; PARAMAGNETISM; PARTICLES; SPIN GLASS STATE