Magnetic structure and glassiness in

Abstract

This work explores the magnetic properties of Fe 0.5 Ni 0.5 PS 3 . The system shows pronounced hysteresis in the magnetic phase transition temperature as a function of the direction of the change in temperature. Field cooled/zero field cooled hysteresis is not pronounced. However, the transition temperature between antiferromagnetic and paramagnetic order occurs at approximately 97 K on cooling, but at 138 K on warming, whether the warming is after zero field or field cooling. This is indicative of magnetic glassiness, and made all the more unusual because all measurements exhibit a transition to a third magnetic phase existing at temperatures below $ 14 K. The intermediate phase relaxes on a laboratory time scale of the order of 48 min, into an antiferromagnetic state whose magnetic structure is, from neutron diffraction, indistinguishable from the low temperature state. This low temperature state shows magnetic ordering consistent with that observed in CoPS 3 and NiPS 3 . Analysis of the neutron measurements shows that the direction of moments cannot be along the b-axis. It is also shown that the moments are unlikely to lie in the c n direction. Therefore, we suggest that the moments lie along the a-axis.

Chemical and magnetic ordering in Fe0.5Ni0.5 PS 3

“…There is no evidence in the neutron scattering results for the time-dependence observed in magnetometry [14]. Measurements made on heating and cooling the sample were identical within experimental error.…”

“…While a low-temperature magnetic phase transition has been reported [14,16] at approximately 13 K, there is no apparent change in the nature of the magnetic correlations around this temperature, as revealed by neutron diffraction -though there are relatively few well-determined magnetic peaks. Data were rebinned to match the gridding of the Brillouin calculation [17], and in doing so some temperature resolution was lost phase transition observed previously [14,16]. Hence, while there is no evidence in these data that the magnetic moment direction or correlation structure changes, there is evidence for some change.…”

“…Mixing these gives rise to some examples of unusual and complex behaviour. For example, Fe 0.5 Mn 0.5 PS 3 is a spin glass [3] while Fe 0.5 Ni 0.5 PS 3 shows a magnetic state whose relaxation towards equilibrium takes two to three hours [14]. Some frustration in a mixed Fe/Ni system is not surprising, given that the magnetic ordering directions in FePS 3 and NiPS 3 are orthogonal.…”

Metall‐Phosphor‐Trichalkogenide (MPCh3): von der Synthese zu aktuellen Energieanwendungen

“…[17][18][19][20] Das Synthesegemisch ist typischerweise ein System aus wenigstens drei Elementen, sodass parasitische Reaktionen und die simultane Bildung mehrerer Phasen ernste Problem bereiten kçnnen. [26,27] In die MPCh 3 -Schichtstruktur kçnnen Spezies wie Alkalimetalle und organische Moleküle (typischerweise Amine) interkalieren. B. eines elementaren Halogens (Cl 2 ,B r 2 ,I 2 ), abgesenkt werden.…”

“…[22] Eine Verbesserung der Leitfähigkeit wird gewçhnlich auf Metall-und/oder S-und P-Plätze mit gemischten Oxidationszahlen zurückgeführt, [49] die die katalytische Leistung des MPCh 3 -Materials beeinflussen. FePS 3 ,M nPS 3 und NiPS 3 [13] wurden am intensivsten untersucht, wobei der Fokus auf dem Volumenkristall lag, [21,26,27,38] während sich Rechnungen zum Spinzustand auf MPCh 3 -Monoschichten konzentrieren. [22] In einem anderen Beispiel wurde die katalytische Aktivitäta uf einem Nanokomposit aus reduziertem Graphenoxid (rGO) und wenigen FePSe 3 -Schichten einer verbesserten Gesamtleitfähigkeit durch das rGO zugeschrieben, das als Leitungskanal fürd en leichten Elektronentransfer fungiert (Abbildung 3a).…”