title: Magnetic anisotropy and spin-glass behavior in single crystalline U2PdSi3.
abstract: We present the magnetic and transport properties of single crystalline U(2)PdSi(3) measured with the magnetic field (H) (or measuring current, I) applied along two typical crystallographic directions, i.e. H ⊥ c-axis and H <parallel> c-axis (or I ⊥ c-axis and I <parallel> c-axis). For both directions, a spin-glass state is confirmed to form at low temperature with the same spin freezing temperature T(f) (=11.5 K), initial frequency shift δT(f) (=0.023) and activation energy E(a)/k(B) (=90.15 K) in zero dc field. Strong anisotropy in magnetic and transport behavior is found to be a significant feature of U(2)PdSi(3). The unusual ferromagnetic-like anomaly in ac susceptibility and dc magnetization curves around T(m)=71 K is observed in the case of H <parallel> c-axis but not in the cases of H ⊥ c-axis. The characteristic temperature T(ir), below which evident irreversible magnetism originated from random spin freezing can be observed, shows much stronger field dependence for H ⊥ c-axis than for H <paraellel> c-axis. Moreover, an unusual finding is that the electrical resistivity measurements indicate the formation of magnetic Brillouin-zone boundary gaps and much larger magnetic scattering for I ⊥ c-axis, while the coherent-Kondo-effect-like behavior is obvious for I <paraellel> c-axis. We also emphasize that no resistivity minimum can be detected down to 2.5 K for either direction. The observed magnetic and transport behaviors are compared with those in polycrystalline U(2)PdSi(3) and other 2:1:3 intermetallic compounds.
authors.affiliation: Institute for Materials Research, Tohoku University, Oarai, Ibaraki, 311-1313, Japan. dxli@imr.tohoku.ac.jp
authors.forename: D X
authors.initials: DX
authors.lastname: Li
authors.forename: A
authors.initials: A
authors.lastname: Kimura
authors.forename: Y
authors.initials: Y
authors.lastname: Haga
authors.forename: S
authors.initials: S
authors.lastname: Nimori
authors.forename: T
authors.initials: T
authors.lastname: Shikama
mesh_terms: D016880:Anisotropy; D003460:Crystallization; D005898:Glass / Q000737:chemistry*; D008280:Magnetics; D008422:Materials Testing; D008968:Molecular Conformation; D010165:Palladium / Q000737:chemistry*; D044367:Phase Transition; D012825:Silicon / Q000737:chemistry*; D014501:Uranium / Q000737:chemistry*
chemical_list: D014501:Uranium; D010165:Palladium; D012825:Silicon