Magnetic and crystallographic properties of NdMn_6 xFe_xSn₆intermetallics

Abstract

Intermetallic compounds of NdMn6−xFexSn6 () were studied by means of x-ray and neutron diffraction techniques and SQUID magnetic measurements in the temperature range of 30–400 K. The substitution of iron for manganese leads to a phase transition whereby NdMn6Sn6 with the HoFe6Sn6 structure (space group Immm) changes to TbFe6Sn6 (space group Cmcm) for NdMn6−xFexSn6 with . The iron atoms prefer to occupy the 8g sites at iron content x<2.0 due to the longest Mn/Fe–Sn bond distance. The Curie temperature (TC) increases from x = 0 to 1.5 and then decreases for the larger iron content. The magnetic moment of the iron sublattice couples ferromagnetically with the manganese and neodymium moments for the x<2.0 samples. Spin reorientation is observed in samples with iron content up to 1.5, and the spin reorientation temperature (Ts) increases with increasing iron content. Except for NdMn4Fe2Sn6, the easy direction of magnetization for all samples is parallel and perpendicular to the (bc) plane of the unit cell at 300 and 30 K, respectively. The easy direction of magnetization for NdMn4Fe2Sn6 is parallel to the a-axis in the entire temperature range mentioned above, as a result of the anisotropic contraction of the unit cell along the (bc) plane.

Mössbauer study of the spin reorientation in pseudobinary alloy Hf0.82Ta0.18Fe2

“…The magnetic structure is consistent with the previous neutron diffraction studies in FM state [13]. The magnetic structure at 6h site at FM state is also similar to the other magnetic compound with Kagome net, such as FeSn, ThMn 2 , some RFe 6 X 6 (X = Ge or Sn) compounds [25][26][27][28].…”

“…[25].The anisotropic contribution was also observed in Fe 3 Sn 2 , FeSn, RFe 6 X 6 (X = Ge or Sn), et al [25][26][27][28][29]. Fig.…”

An iron-57 and tin-119 Mössbauer spectral study of NdMn6−xFexSn6

“…The substitution of Fe for some of the Mn in the RMn 6 Sn 6 compounds generally leads to a decrease in both the Curie temperature and the saturation magnetization. However, unexpectedly, an increase in Curie temperature and saturation magnetization has been observed [6][7][8] both in SmMn 5.5 Fe 0.5 Sn 6 and in NdMn 6−x Fe x Sn 6 when x 2. X-ray and neutron diffraction studies indicate, at all temperatures studied [8], that NdMn 6 Sn 6 crystallizes with the HoFe 6 Sn 6 I mmm structure, whereas NdMn 6−x Fe x Sn 6 , with 0.5 x 2.0, crystallizes with the TbFe 6 Sn 6 Cmcm structure.…”

“…However, unexpectedly, an increase in Curie temperature and saturation magnetization has been observed [6][7][8] both in SmMn 5.5 Fe 0.5 Sn 6 and in NdMn 6−x Fe x Sn 6 when x 2. X-ray and neutron diffraction studies indicate, at all temperatures studied [8], that NdMn 6 Sn 6 crystallizes with the HoFe 6 Sn 6 I mmm structure, whereas NdMn 6−x Fe x Sn 6 , with 0.5 x 2.0, crystallizes with the TbFe 6 Sn 6 Cmcm structure. The fractional iron occupancy of the three transition metal sites in the NdMn 6−x Fe x Sn 6 compounds was obtained [8] from powder neutron diffraction Rietveld refinements.…”

Crystal Structure and Magnetic Properties of HfFe6Ge6-Type ErMn6–xCoxGe6 (x = 0–1.45) Alloys

“…The ErMn 6 Ge 6 systems are of interest for their magnetic properties with at least two ordering temperatures; the compound has an antiferromagnetic order near 470 K and a second jump near 100 K. ,, In the past, the major attention of RMn 6 Ge 6 systems have been focused on the investigation of their crystallographic, magnetic, and electronic structures, − and the GMR effect is related to the magnetic transition, which can be achieved by adjusting the interaction of Mn–Mn and R–Mn sublattices. The RMn 6 Ge 6 systems consist of Mn–(R, Ge)–Mn and Mn–Ge–Ge–Ge–Mn slabs that are alternately (−Mn–(R,Ge)–Mn–Ge–Ge–Ge–Mn−) stacked along the c -axis; the coupling between the Mn moments in a layer is of the ferromagnetic (FM) type, whereas the coupling between Mn moments in adjacent layers is of the antiferromagnetic type, and it can be significantly changed by appropriately selecting different elements to replace Mn sites. − …”