Experimental and theoretical study of magnetic ordering and local atomic polarization in Ru-substitutedLu2Fe17

Abstract

The distribution of magnetic moments in the iron-rich intermetallic compound Lu 2 Fe 17 with Fe partly substituted by Ru has been investigated on Lu 2 Fe 16.5 Ru 0.5 by using several techniques. The crystal structure and temperature evolution of the magnetic structure was studied using high resolution and high flux neutron powder diffractometers. In contrast to the parent Lu 2 Fe 17 , which transforms on cooling from an antiferromagnetic to a ferromagnetic state, Lu 2 Fe 16.5 Ru 0.5 is an antiferromagnet (Néel temperature T N = 208 K) down to the lowest temperatures. The magnetic polarization at the lutetium L 2,3 absorption edges, iron K and ruthenium L 2 edges was studied by x-ray magnetic circular dichroism (XMCD) on a single crystal of Lu 2 Fe 16.5 Ru 0.5 in a magnetic field of 3 T, i.e., above the field-induced metamagnetic transition. The Ru XMCD signal proves the existence of induced magnetic polarization parallel to the dominant Fe sublattice magnetization. A corresponding theoretical analysis in the framework of the local spin density formalism is provided in order to discern the structural disorder effects and magnetism in the system.

Role of “Dumbbell” Pairs of Fe in Spin Alignments and Negative Thermal Expansion of Lu2Fe17-Based Intermetallic Compounds

“…Then precipitation of the α-Fe phase emerges for the Lu 2−x Fe 17 compounds. 24 It is interesting that the characteristic peaks of (300) and (004) keep moving inversely (Figure 1d) for the 2:17 phase, indicating that the lattice parameters are distinctly tuned with decreasing Lu content. The similar tendency between the lattice parameter and dumbbell occupation reveals that an increase of the dumbbell content intimately affects the lattice parameters with the Lu content (Figure S3).…”

“…This suggests that the disorder substitutions of dumbbells gradually approach the saturation of solid solubility. Then precipitation of the α-Fe phase emerges for the Lu 2– x Fe 17 compounds . It is interesting that the characteristic peaks of (300) and (004) keep moving inversely (Figure d) for the 2:17 phase, indicating that the lattice parameters are distinctly tuned with decreasing Lu content.…”

Manipulating Spin Alignments of (Y,Lu)1.7Fe17 Intermetallic Compounds via Unusual Thermal Pressure

“…In Figure S1, the SEM–EDS linear sweep pattern of the Lu 1.7 Fe 17 compound indicated that the two phases are separate and the α–Fe is embedded in the matrix of the 2:17 phase. The ideal Th 2 Ni 17 -type R 2 Fe 17 compounds are derived from the CaCu 5 -type structure R Fe 5 (space group: P 6/ mmm ) with pairs of Fe atoms (denoted as dumbbells) sequentially substituting R atoms on the triple screw axis along the c axis (Figure c) . Unfortunately, the refinements of SXRD patterns indicate that there exist varying extents of lattice distortions in Y 1.7−δ Lu δ Fe 17 resulting from the partially disordered substitutions of the dumbbells (Figure d).…”

Magnetic phase diagrams of Gd-H, Tb-H, Dy-H systems

“…R 2 Fe 17 (R = Ce [20] and Lu [21]). The temperatures of magnetic phase transitions and the magnetic structures are extremely sensitive to the interstitial impurity atoms (hydrogen, in particular) [22,23], to substitutional atoms [24] and high pressure [25]. The magnetic phase diagrams of such compositions have been obtained and studied extensively in literature [26].…”