Magnetic phases of skyrmion-hostingGaV4S8−ySey(y=0,2

Abstract

Citation for published item:prnkeD u¡ evin tF eF nd ruddrtD fenjmin wF nd rikenD homs tF nd ioD pn nd flundellD tephen tF nd rttD prnis vF nd grisntiD wrt nd frkerD toel eF F nd glrkD tewrt tF nd § tefn § i § D ele § s nd rtnenD woni giomg nd flkrishnnD qeeth nd vnsterD om @PHIVA 9wgneti phses of skyrmionEhosting qRVyey @y a HD PD RD VA proed with muon spetrosopyF9D hysil review fFD WV @SAF HSRRPVF Further information on publisher's website: eprinted with permission from the emerin hysil oietyX prnkeD u¡ evin tF eFD ruddrtD fenjmin wFD rikenD homs tFD ioD pnD flundellD tephen tFD rttD prnis vFD grisntiD wrtD frkerD toel eF FD glrkD tewrt tFD § tefn § i § D ele § sD rtnenD woni giomgD flkrishnnD qeeth vnsterD om @PHIVAF wgneti phses of skyrmionEhosting qRVyey @y a HD PD RD VA proed with muon spetrosopyF hysil eview f WV@SAX HSRRPVF @PHIVA y the emerin hysil oietyF eders my viewD rowseD ndGor downlod mteril for temporry opying purposes onlyD provided these uses re for nonommeril personl purposesF ixept s provided y lwD this mteril my not e further reproduedD distriutedD trnsmittedD modi(edD dptedD performedD displyedD pulishedD or sold in whole or prtD without prior written permission from the emerin hysil oietyFAdditional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We present the results of a muon-spin spectroscopy investigation of GaV 4 S 8−y Se y with y = 0, 2, 4, and 8. Zero-field measurements suggest that GaV 4 Se 8 and GaV 4 S 8 have distinct magnetic ground states, with the latter material showing an anomalous temperature dependence of the local magnetic field. It is not possible to evolve the magnetic state continuously between these two systems, with the intermediate y = 2 and 4 materials showing glassy magnetic behavior at low temperature. The skyrmion lattice (SkL) phase is evident in the y = 0 and 8 materials through an enhanced response of the muon-spin relaxation to the emergent dynamics that accompany the SkL. For our polycrystalline samples of GaV 4 Se 8 , this enhanced dynamic response is confined to a smaller region of the magnetic field-temperature phase diagram than the previous reports of the SkL in single crystals.

Magnetism and Néel skyrmion dynamics in GaV4S8−ySey

“…This confirms the suggestion in Ref. [21] that the SkL in polycrystalline samples is confined to a smaller region of the phase diagram than in singlecrystal samples. A frequency of around 16 GHz for the zerotemperature excitation mode is found, again consistent with other skyrmion materials.…”

“…2(a)-2(c) with a black line] with B 2 corresponding to the high-field peak (red line). The unusual decrease in B 2 with decreasing temperature, along with a change in the fraction of muons subject to this magnetic field, reflects the continuous evolution of the magnetic state, providing further evidence for a smooth crossover between the FM* and the C states, rather than a sharp phase transition [21]. The crossover region 5 T 9 K [shaded in Fig.…”

“…[21,22]. Whereas polycrystalline samples are likely to exhibit a different magnetic phase diagram to those of single crystals (whose behavior varies depending on the alignment between applied field and crystallographic axes), we have previously shown that the SkL can be identified unambiguously [21]. AC magnetic susceptibility ( Fig.…”

“…2(a)-2(c). Simulations of the magnetic field [31,32] at the muon-stopping sites [21] for the ground-state magnetic structures proposed for GaV 4 S 8 [17,22,33] show that the distribution most closely resembles the ferromagneticlike (FM*) state [ Fig. 3(a)] at low temperatures, and the incommensurate cycloidal (C) state at higher temperatures.…”

“…Since there are muon-stopping sites around the cluster, this provides an explanation for the observed large magnetic-field B 3 . The change in spin density may also lead to altered exchange pathways, which, upon increased substitution, could lead to the glasslike magnetic ground state seen for y = 2 and y = 4 [21] where multiple different exchange pathways (depending on the local substitution level) cannot be simultaneously satisfied.…”