Stability of the modulated states in ErNi{sub 2}B{sub 2}C: A neutron diffraction study of chemically doped samples

Journal Article · Sat Oct 01 04:00:00 EDT 2005 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.72.144521· OSTI ID:20719620

El Massalami, M; Galera, R -M; Schmitt, D; Ouladdiaf, B; Takeya, H ^[1]

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1. Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21945-970 Rio de Janeiro (Brazil) and Laboratoire de Magnetisme Louis Neel-CNRS, Boite Postale 166, 38042 Grenoble Cedex 9 (France) and Institut Laue-Langevin, Boite Postale 156, 38042 Grenoble Cedex 9 (France)

Neutron-diffraction measurements on Er{sub 0.8}R{sub 0.2}Ni{sub 2}B{sub 2}C (R=Tb,Lu) and ErNi{sub 1.9}Co{sub 0.1}B{sub 2}C have been carried out to investigate the influence of chemical doping on the stability of the modulated states in ErNi{sub 2}B{sub 2}C. Within the magnetically ordered phase and down to 1.6 K (the lowest measured temperature), the powder diffractograms of Lu and Tb doped compounds are consistent with a transverse sine-modulated (fundamental) mode. A neutron diffraction study on a single-crystal Er{sub 0.8}Lu{sub 0.2}Ni{sub 2}B{sub 2}C recorded at 1.8 K has confirmed the absence of higher order harmonics. In contrast, the low-temperature patterns of the Co doped compound reveal the presence of all the odd-order harmonics up to the fifth-order satellite, reminiscent of the structure of the undoped ErNi{sub 2}B{sub 2}C below the weak-ferromagnetic transition point T{sub WF}=2.1 K: a squared-up, noncompensated long-period antiferromagnetic state. The above-mentioned findings are consistent with the conclusions drawn from our previous specific-heat and magnetization measurements on the same compounds: on lowering the temperature further below T{sub N}, both ErNi{sub 2}B{sub 2}C and Co doped compounds undergo a spontaneous transition at T{sub WF}. In contrast, for the Lu and Tb doped compounds, no such second magnetic phase transition was observed down to 1 K; eventually the squaring-up of these structures, as required by entropy arguments, should occur but at temperatures lower than 1 K.

• OSTI ID: 20719620
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 14 Vol. 72; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
COBALT COMPOUNDS
DOPED MATERIALS
ENTROPY
ERBIUM BORIDES
ERBIUM CARBIDES
HARMONICS
LUTETIUM COMPOUNDS
MAGNETIZATION
MONOCRYSTALS
NEUTRON DIFFRACTION
NICKEL COMPOUNDS
PHASE TRANSFORMATIONS
POWDERS
SPECIFIC HEAT
STABILITY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TERBIUM COMPOUNDS