HfMnSb₂: A Metal‐Ordered NiAs‐type Pnictide with a Conical Spin Order

Abstract

The NiAs-type structure is one of the most common structures in solids, but metal order has been almost exclusively limited to chalcogenides. The synthesis of HfMnSb2 is reported with a novel metal-ordered NiAs-type structure. HfMnSb2 undergoes a conical spin order below 270 K, in marked contrast to conventional magnetic order observed in NiAs-type pnictides. We argue that the layered arrangement of Hf and Mn makes it a quasi 2D magnet, where the Mn layers with localized magnetic moments (Mn(2+) ; S=5/2) can interact only through RKKY interactions, instead of metal-metal bonding that is otherwise dominant for typical NiAs-type pnictides. This result suggests that controlling order-disorder in NiAs-type pnictides enables a study of 2D-to-3D crossover behavior in itinerant magnetic system.

Ambient and High Pressure CuNiSb2: Metal-Ordered and Metal-Disordered NiAs-Type Derivative Pnictides

“…The total energy of stabilizing the metal-ordered NiAs-derived structure is lower than that of the NiAs-type (P6 3 /mmc) structure, as discussed later in the electronic structure section. The recent report of HfMnSb 2 is another example of "112" pnictides with metal-ordering, 25 which is attributed to the large size difference between Hf (r = 1.75 Å) and Mn (r = 1.39 Å) atoms, similar to the scenario observed in AuNiSn 2 and AuCuSn 2 . 23 The average size of obtained polycrystalline particles is less than 100 μm, based on the SEM-EDX results (Figure S2).…”

“…In addition to the reported chalcogenides, this metal-ordered NiAs-derived structure has also been observed in other “112” intermetallic compounds. AuCuSn 2 and AuNiSn 2 are two examples of stannides in which Au and Cu/Ni have different atom sizes. , In terms of pnictides, an experimental compound HfMnSb 2 was reported in 2016 . It is not surprising that Hf and Mn atoms are ordered due to the large size difference.…”

“…23,24 In terms of pnictides, an experimental compound HfMnSb 2 was reported in 2016. 25 It is not surprising that Hf and Mn atoms are ordered due to the large size difference. This is an interesting compound that exhibits conical spin order due to Mn layers.…”

Variable Temperature Crystal Structure of Cu4TiTe4

“…and this transition may significantly influence the physical properties of the materials. Many chalcogenide materials which undergo such phase transition show a certain jump in their physical properties e. g., thermoelectric property, [9][10][11] superionic conductivity, [12][13][14] magnetic property, [15,16] etc. The tendency to exhibit thermally induced order-disorder phase transition has been noticed in a group of copper and silver-based chalcogenides due to their typical structural features.…”