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Title: Magnetic properties and magnetocaloric effect of NdMn{sub 2−x}Cu{sub x}Si{sub 2} compounds

Structural and magnetic properties of NdMn{sub 2−x}Cu{sub x}Si{sub 2} compounds (x = 0–1.0) have been investigated by high intensity x-ray and resolution neutron diffraction (3–450 K), specific heat, dc magnetization, and differential scanning calorimetry measurements. Substitution of Cu for Mn leads to an increase in the lattice parameter a but a decrease in c at room temperature. Two magnetic phase transitions have been found for NdMn{sub 2−x}Cu{sub x}Si{sub 2} compounds with T{sub N} for the antiferromagnetic ordering of Mn-sublatttice and T{sub C} for the Nd-sublattice ferromagnetic ordering, respectively. T{sub C} increases significantly with increasing Cu content from 36 K at x = 0 to 100 K at x = 1.0. Moreover, it is found that the order of magnetic phase transition around T{sub C} also changes from first order at x < 0.6 to second order transition for x ≥ 0.6. The spontaneous magnetization found to decrease with the increase in Cu concentration which can be understood in the term of the dilution effect of Cu for Mn. The values of −ΔS{sub M} around T{sub C} decrease with increasing x from 27 J kg{sup −1} K{sup −1} for x = 0 to 0.5 J kg{sup −1} K{sup −1} for x = 1.0 under 0–5 T field. Refinement of neutron diffraction patterns for x = 0.2 confirms the magnetic states detected by magneticmore » study and also indicates that the lattice constants a and c show a distinct variation around T{sub C}.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ; ;  [4] ;  [5] ; ;  [1] ;  [6]
  1. Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia)
  2. (Malaysia)
  3. (Australia)
  4. Bragg Institute, ANSTO, Lucas Heights, NSW 2234 (Australia)
  5. Australian Synchrotron, 800 Blackburn Rd, Clayton 3168 (Australia)
  6. School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Canberra, ACT 2600 (Australia)
Publication Date:
OSTI Identifier:
22273809
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; ANTIFERROMAGNETISM; CALORIMETRY; CONCENTRATION RATIO; COPPER COMPOUNDS; DIFFERENTIAL THERMAL ANALYSIS; LATTICE PARAMETERS; MAGNETIC PROPERTIES; MAGNETIZATION; MANGANESE SILICIDES; NEEL TEMPERATURE; NEODYMIUM COMPOUNDS; NEUTRON DIFFRACTION; PHASE TRANSFORMATIONS; SPECIFIC HEAT; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; X-RAY DIFFRACTION