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Title: Investigation of dielectric relaxation, Jahn-Teller distortion, and magnetic ordering in Y substituted Pr{sub 1−x}Y{sub x}MnO{sub 3} (0.1 ≤ x ≤ 0.4)

We report structural, magnetic, and dielectric properties of the perovskite compound Pr{sub 1−x}Y{sub x}MnO{sub 3} (0.1 ≤ x ≤ 0.4) studied using dc magnetization, ac susceptibility, neutron powder diffraction, and dielectric techniques. These compounds crystallize in orthorhombic space group (Pnma) in the temperature range 5–300 K. The Mn-O-Mn bond angle decreases with the Y substitution along with an increase in the Jahn-Teller distortion. The Jahn-Teller distortion for Pr{sub 0.9}Y{sub 0.1}MnO{sub 3} shows an anomalous change near 50 K, below which it falls sharply. Neutron powder diffraction patterns of all reported compositions at low temperature constitute additional magnetic Bragg peaks that suggest magnetic ordering. Magnetic reflections were indexed in the nuclear lattice with the propagation vector k = (0, 0, 0). Rietveld refinement of powder patterns conform to A type antiferromagnetic ordering where moments are aligned ferromagnetically in a–c plane and coupled nearly antiferromagnetically along b-axis resulting in a net ferromagnetic component along the b-direction. The antiferromagnetic transition temperature was deduced from dc magnetization and ac susceptibility data. The transition temperature decreases by nearly 22 K (from 81 K to 59 K) as yttrium content (x) increases from 0.1 to 0.4. Measurements reveal strong frequency dispersion in dielectric constant and dielectric loss. Activation energy and relaxation time are estimated from the Arrheniusmore » plot. It is further shown that relaxation behaviour is altered with yttrium doping concentration.« less
Authors:
;  [1] ;  [2] ; ;  [3] ;  [4] ;  [1] ;  [5]
  1. Department of Physics, Indian Institute of Science, Bangalore 560012 (India)
  2. Highly Correlated Matter Research Group, Physics Department, P.O. Box 524, University of Johannesburg, Auckland Park 2006 (South Africa)
  3. Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
  4. JCNS 2/Peter Grünberg Institute 4, Forschungszentrum Jüelich, 52425 Jüelich (Germany)
  5. (India)
Publication Date:
OSTI Identifier:
22413202
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 9; 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; ANTIFERROMAGNETISM; BOND ANGLE; BRAGG CURVE; CONCENTRATION RATIO; DIELECTRIC MATERIALS; JAHN-TELLER EFFECT; MAGNETIZATION; MANGANATES; NEUTRON DIFFRACTION; ORTHORHOMBIC LATTICES; PERMITTIVITY; POWDERS; PRASEODYMIUM COMPOUNDS; REFLECTION; RELAXATION TIME; TEMPERATURE DEPENDENCE; TRANSITION TEMPERATURE; YTTRIUM COMPOUNDS