G. Will

The magnetic structure of ErFe4Al8 and TbFe4Al8

Abstract ErFe4Al8 and TbFe4Al8 were studied by neutron diffraction and their magnetic structures were determined. Antiferromagnetic ordering of the Fe moments begin around 165 K and is followed by ferromagnetic ordering of the rare-earth moments near 30 K.

The magnetic structure of antiferromagnetic DyVO4

The magnetic and crystallographic structure of DyVO4 has been determined by neutron diffraction on a powdered sample. The two observed lambda -type anomalies in the specific heat at 13.8 and 3.0 K are explained by a quadrupole ordering followed by an antiferromagnetic transition. At 3.0 K DyVO4 undergoes a transition to a collinear antiferromagnetically ordered state with the moments parallel to the b axis. The magnetic moment is 9/0 mu B at 1.85 K. The nuclear scattering does not allow for a crystallographic phase transition, either at 13.8 K or at 3.0 K. In order to describe the magnetic structure properly the symmetry has to be reduced, however, to orthorhombic symmetry, space group Imma-D2k28.

Magnetic structure of the TbNiC2 ternary carbide

Abstract The magnetic structure of the TbNiC 2 ternary carbide was studied by neutron diffraction. The crystal structure of this compound is orthorhombic, space group Amm2, with Neel temperature equal to 25 K. The magnetic cell, at 16 K, is four times larger than the chemical one, with a wave vector k = [ 1 2 1 2 0] . The terbium moment value and direction are μ Tb = 6.8μ B along the c -axis of the crystal. The crystal field calculations on the Tb 3+ site with a molecular field parallel to c , give a magnetic model which agrees with the observed one.

Magnetic structure determination of NdNiC2 and TmNiC2 by neutron diffraction

Isostructural orthorhombic NdNiC2 and TmNiC2 reveal collinear antiferromagnetic structures with magnetic propagation vectors [12120] and [0, 0, 1], respectively. In NdNiC2, ferromagnetic (110) planes are coupled pairwise in opposite spin orientations; in TmNiC2, adjacent ferromagnetic (001) planes are coupled antiferromagnetically. The magnetic moments are oriented parallel to the a-axis and have values of 2.7μB (Nd) and 3.3μB (Tm) at 4 K.

The antiferromagnetic structure of ErNiC2 ternary carbide

Abstract The magnetic structure of the orthorhombic ErNiC 2 ternary compound was studied by neutron diffraction. The structure is collinear antiferromagnetic. The Neel temperature is 8 K. The magnetic unit cell has the same dimensions as the chemical one with a magnetic propagation vector k = [0,0,1]. The erbium moments are oriented along the crystallographic a -axis and have a value of 8.7 μ B at 4.2 K.

Magnetic properties of RCoC2 (R = Y, Gd,Tb) compounds

Abstract The magnetic properties of YCoC 2 , GdCoC 2 and TbCoC 2 have been studied by means of susceptibility and neutron diffraction measurements. These properties are due only to the rare earth sublattice. TbCoC 2 is ferromagnetically ordered below 27 K with moment orientations along the crystallographic a -axis; the terbium moment is 8.4(2)μ B at 4.2 K.

The magnetic phase diagram of ErB4

Abstract The magnetic phase diagram of ErB 4 was studied on a single crystal by neutron diffraction in the temperature range of 4.2 to 17 K with outer magnetic fields up to 70 kOe. The H - T phase diagram shows three magnetic phases (antiferromagnetic, ferrimagnetic and ferro-paramagnetic) and a triple point at T t = (11.7 ± 0.2) K and H t = (21 ± 2) kOe.

Neutron diffraction study of RNiC2 (R =rare earth) compounds

Abstract Low temperature neutron diffraction has been performed on the series of isostructural RNiC 2 compounds with R≡ Pr, Nd, Tb, Dy, Ho, Er and Tm (space group Amm 2). The rare earth sublattices (with the exception of PrNiC 2 ) are found to order antiferromagnetically. Structural parameters and magnetic moment configurations have been determined. A systematic variation of the magnetic structures according to the sequence of rare earth elements is discussed.

Neutron diffraction study of antiferromagnetic DyAsO4

The magnetic structure of DyAsO4 has been determined by neutron diffraction on a powdered sample. DyAsO4 undergoes a transition to a non-collinear antiferromagnetically ordered state at 2.5 K, with an inclination of the magnetic moments of phi b=22 degrees relative to the b axis in the ab plane. The magnetic space group is PI212121 (orthorhombic symmetry). The magnetic moment is 8.6 mu B at 2.2 K. The temperature behaviour of the magnetization is in agreement with an Ising magnet. The crystallographic parameters are determined and possible crystallographic phase transitions are discussed.

Neutron diffraction investigation of ferromagnetic TbB2

Abstract The ferromagnetic ordering of TbB2, deduced from magnetization measurements, was confirmed by neutron diffraction. Curie temperature is 151 K, and the observed moment is 8.3 μB/Tb3+ at 5 K. The form factor of Tb3+ in TbB2 differs significantly from that of metallic terbium.