PrRu{sub 2}Si{sub 2}: A giant anisotropic induced magnet with a singlet crystal-field ground state
- Interfacultair Reactor Instituut, Delft University of Technology, 2629 JB Delft (The Netherlands)
- Commissariat a lEnergie Atomique, Departement de Recherche Fondamentale sur la Matiere Condensee, Service de Physique Statistique, Magnetisme et Supraconductivite, F-38054 Grenoble cedex 9 (France)
- van der Waals-Zeeman Laboratorium, Universiteit van Amsterdam, 1018 XE Amsterdam (The Netherlands)
The magnetic properties of PrRu{sub 2}Si{sub 2} have been investigated experimentally by specific heat, single-crystal magnetization, {sup 141}Pr M{umlt o}ssbauer and muon spectroscopies, neutron powder diffraction, and inelastic neutron scattering, leading to the determination of its zero-field phase diagram and its crystal electric-field energy levels below 40 meV. PrRu{sub 2}Si{sub 2} undergoes a magnetic phase transition at T{sub N} {approx_equal} 16 K to an axial incommensurate sine-wave magnetic structure characterized by a wave vector {tau} = (0.133, 0.133, 0), followed by a first-order phase transition at T{sub C} {approx_equal} 14.0 K to an axial ferromagnetic structure. The lowest crystal electric-field states are the two singlets {vert_bar}{Gamma}{sub t1}{sup (1)}{r_angle} and {vert_bar}{Gamma}{sub t2}{r_angle} separated by 2.25 meV. The low-temperature properties are described by a Hamiltonian identical to that of an Ising system with a transverse magnetic field. Since the ratio of the exchange energy to the energy splitting between the singlets is sufficiently large, it exhibits spontaneous magnetization. The nature of the two singlet states explains the giant magnetic anisotropy. The random-phase approximation predicts the value of the high-field magnetization but yields a low-field magnetization too small by {approximately} 15{percent}. Possible application of our results to uranium intermetallic compounds is pointed out. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 632629
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 14; Other Information: PBD: Oct 1997
- Country of Publication:
- United States
- Language:
- English
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