A single-crystal neutron diffraction study of the magnetization density in Fe2Zr

A single-crystal neutron diffraction study of the cubic Laves phase Fe2Zr at 4.2 K has been made using both polarized and unpolarized incident beams. The samples were prepared from high-purity zirconium and iron and exhibited resistance ratios (rho 293 K/rho 4.2 K) of typically 95, indicative of samples with good long-range order and homogeneity. The material has a Curie temperature of 604(2) K and a cell dimension of a=7.063(1) AA at ambient temperature in agreement with previous measurements for this composition by others. The saturation magnetization of 3.46(1) mu B/formula unit at 4.2 K is higher than previously observed. The magnetization density of the sample has been fitted by a weighted least-squares procedure to a multipole model of the iron moment based on free-atom wavefunctions for Fe2+. The symmetry at the iron site is 3m and the independent symmetry-allowed multipoles up to l=4 are Y00, Y20, Y40 and Y43-: these have amplitudes 2.11(3), 0.03(2), 0.16(4) and -0.30(4) mu B respectively. The magnetization at the Zr site is negative and is modelled by a single spherical term, Y00=-0.32(5) mu B. The remaining magnetization of -0.44 mu B/formula unit is associated with diffuse density. These findings are discussed in the light of band structure calculations and previous studies of magnetic Laves phases.

[1]  H. Yamada.  Electronic structure and magnetic properties of the cubic laves phase transition metal compounds , 1988 .

[2]  T. Dumelow,et al.  Pressure dependence of the distribution of hyperfine fields in ZrFe2 and Zr(Nb)Fe2 , 1987 .

[3]  H. Yamada,et al.  Electronic structure and magnetic properties of the cubic Laves phase compounds AFe2 (A=Zr, Lu and Hf) , 1986 .

[4]  A. Heidari,et al.  Local moment formation at dilute transition impurities in ferromagnetic ZrFe2 , 1986 .

[5]  K. Schwarz,et al.  Binding mechanism and itinerant magnetism of ZrFe2 and YFe2 , 1985 .

[6]  W. Pickett,et al.  Electronic structure, superconductivity, and magnetism in the C15 compounds ZrV/sub 2/, ZrFe/sub 2/, and ZrCo/sub 2/ , 1983 .

[7]  G. Hilscher.  Onset of magnetism in concentrated ternary alloys II: Laves phase compounds A(Fe1-xBx)2 (A = Y, Zr, U; B = Mn, Co and Al) , 1982 .

[8]  Yasuyuki Nakamura,et al.  Magnetic properties and Mossbauer effects of Zr(Fe1-xCox)2 , 1979 .

[9]  T. Nakamichi,et al.  Electrical Resistivity of Laves Phase Compounds Containing Transition Elements I. Fe2A (A=Sc, Y, Ti, Zr, Hf, Nb, and Ta) , 1975 .

[10]  P. Coppens,et al.  Extinction within the limit of validity of the Darwin transfer equations. I. General formalism for primary and secondary extinction and their applications to spherical crystals , 1974 .

[11]  A. Miedema,et al.  Thermal expansion of ZrFe2 and some rare-earth iron compounds , 1973 .

[12]  K. Buschow,et al.  Pressure dependence of the Curie temperature of intermetallic compounds of iron and rare‐earth elements, Th, and Zr , 1973 .

[13]  K. Kanematsu,et al.  Magnetic Moment in Laves Phase Compound. II. : Zr(Fe_ Mn_x)_2 and Zr(Fe_ Co_x)_2 , 1971 .

[14]  K. Buschow,et al.  Magnetic Properties of some Cubic Rare‐Earth‐Iron Compounds of the Type RFe2 and RxY1−xFe2 , 1970 .

[15]  K. Kanematsu.  Structural and Magnetic Properties of Pseudobinary System (Zr 1− x Nb x )Fe 2 , 1969 .

[16]  Mikio Yamamoto,et al.  CRYSTAL STRUCTURES AND MAGNETIC PROPERTIES OF THE INTERMETALLIC COMPOUND Fe$sub 2$Zr. , 1968 .

[17]  R. S. Craig,et al.  Structural and Magnetic Characteristics of TiFe2–ZrFe2 and ZrCo2–ZrFe2 Alloys , 1963 .

[18]  P. Brown,et al.  THE ATOMIC MOMENTS AND HYPERFINE FIELDS IN Fe$sub 2$Ti AND Fe$sub 2$Zr , 1962 .

[19]  S. Matsumoto.  Analysis of Nucleon-Nucleus Collision of Energy around 100 GeV , 1962 .

[20]  A. Freeman.  Atomic scattering factors for spherical and aspherical charge distributions , 1959 .

[21]  D. Givord,et al.  3d magnetism in LuFe2 , 1980 .

[22]  W. Brückner,et al.  Magnetic Properties of ZrFe2 and TiFe2 within Their Homogeneity Range , 1968 .

[23]  W. Brückner,et al.  Atomie Arrangement in the Homogeneity Range of the Laves Phases ZrFe2 and TiFe2 , 1967 .