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Title: Doping dependent magnetism and exchange bias in CaMn{sub 1−x}W{sub x}O{sub 3} manganites

Magnetic properties of CaMn{sub 1−x}W{sub x}O{sub 3} (0 ≤ x ≤ 0.1) have been investigated, and the research was focused on the exchange bias (EB) phenomenon in CaMn{sub 0.93}W{sub 0.07}O{sub 3}. Magnetic ground state was found to be dependent on tungsten doping level and the following states were distinguished: (i) G-type antiferromagnetic (AFM) state with a weak ferromagnetic (FM) component at x = 0 and 0.04; (ii) mostly orbitally ordered C-type AFM at x = 0.07 and 0.1. For the studied manganites, spontaneous magnetization increases sharply with increasing doping level reaching M{sub 0} ≈ 9.5 emu/g at T = 10 K for x = 0.04, and then decreases rapidly reaching zero for x = 0.1. Exchange bias effect, manifested by vertical and horizontal shifts in the hysteresis loop for field cooled sample, has been observed in CaMn{sub 0.93}W{sub 0.07}O{sub 3}. Exchange bias field, coercivity, remanence asymmetry, and magnetic coercivity depend strongly on temperature, cooling field, and maximal measuring field. Horizontal and vertical shifts of magnetization loop sharply decrease with increasing temperature and vanish above 70 K, whereas coercivity and magnetic coercivity disappear only above 100 K (temperature of transition to the G-type AFM state). The exchange bias field H{sub EB} increases with increasing cooling field H{sub cool} and goes through a broad maximum atmore » 40 kOe, while the remanence asymmetry increases monotonously in the entire investigated cooling field range, up to 50 kOe. For the compound with x = 0.07, the size of the FM regions ≈2 nm was estimated from the dependence of exchange bias field H{sub EB} upon H{sub cool}. It is suggested that the exchange bias originates from interface exchange coupling between small FM clusters and the G-type AFM phase inside the primary C-type orbitally ordered AFM phase.« less
Authors:
;  [1] ;  [2] ;  [3] ; ;  [2] ;  [4] ; ; ;  [5] ;  [1] ;  [6]
  1. Department of Physics, Ben-Gurion University of the Negev, 84105 Beer-Sheva (Israel)
  2. Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02-668 Warsaw (Poland)
  3. (Ukraine)
  4. The Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)
  5. Institute of Metal Physics, Ural Branch of RAS, Kovalevskaya Street 18, Ekaterinburg 620990 (Russian Federation)
  6. (Poland)
Publication Date:
OSTI Identifier:
22314395
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 9; 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; ANTIFERROMAGNETISM; ASYMMETRY; ATOMIC FORCE MICROSCOPY; AUGMENTATION; COERCIVE FORCE; COOLING; GROUND STATES; HYSTERESIS; INTERFACES; MAGNETIC PROPERTIES; MAGNETIZATION; TUNGSTEN