Evidence of a cluster spin-glass phase in the skyrmion-hosting GaMo₄S₈ compound

Abstract

GaMo4S8, is a poorly known lacunar spinel where skyrmions have only been reported very recently. It belongs to the AM4X8 family, where A is a post-transition metal, M is a...

Synthesis and Structural and Magnetic Properties of Polycrystalline GaMo4Se8

“…GaMo 4 S 8 is also a Mott insulator, with ferromagnetic and cycloidal spin ordering below T C = 19 K [4,32,33]. Our previous work proved the existence of a cluster spin-glass phase close to T C in pollycristalline GaMo 4 Se 8 [34]. In the case of GaMo 4 Se 8 , it orders at T C = 28 K and the Jahn-Teller distortion occurs at T JT at 51 K. Recent synchrotron powder diffraction studies on polycrystalline GaMo 4 Se 8 disclosed that below T JT the rhombohedral R3m phase coexists with a metastable orthorhombic Imm2 phase [30,31].…”

“…GaMo 4 Se 8 was synthesised in polycrystalline form by a simple two-step method, similar to that used in our previous work for GaMo 4 S 8 [34]. In the first step, the precursor MoSe 2 was synthesised by reacting stoichiometric amounts of molybdenum (foil, thickness 0.1 mm, 99.9%, Sigma Aldrich, St. Louis, MO, USA) and selenium (pellets, <5 mm, 99.99%, Sigma Aldrich) with a molar proportion of 1:2 in evacuated sealed quartz tubes.…”

Dressed jeff-1/2 objects in mixed-valence lacunar spinel molybdates

“…It can also imply quasi-localized ligand-hole states, i. e., ligand mixed valency, as shown for underdoped cuprates 3,4 or for the spin-Peierls compound NaV 2 O 5 5,6 . Here we explore the mixed valence landscape in the molybdates GaMo 4 S 8 and GaMo 4 Se 8 , lacunar-spinel quantum magnets displaying remarkable properties, e. g., modulated cycloidal and Néel-type skyrmion-lattice states with sub-10 nm periodicity that are coupled to ferroelectric polarization 7 , a plethora of ferroelectric domain boundaries and junctions 8 , and a cluster spin-glass phase 9 . Using advanced wave-functionbased quantum chemical computational schemes, we show that the peculiar interplay of electronic correlations and spin-orbit interactions in these materials sets the stage for interesting physics and new insights: the dressing of a j eff = 1/2 spin-orbit-coupled state 10 with virtual valence space excitations.…”