Magnetic order, field-induced phase transitions and magnetoresistance in the intercalated compound Fe_0.5TiS₂

Abstract

Measurements of the magnetic susceptibility, magnetization, electrical resistivity and neutron diffraction have been performed for the compound Fe(0.5)TiS(2) in which Fe atoms are intercalated between S-Ti-S tri-layers. It has been shown that this compound with a monoclinic crystal structure exhibits an antiferromagnetic (AF) ground state below the Néel temperature T(N) ≈ 140 K. Small deviations from the stoichiometry and some disordering effects caused by the additional low-temperature heat treatment do not affect substantially the AF state in Fe(0.5)TiS(2). According to neutron diffraction data the magnetic structure at 2 K is described by the propagation vector k = (1/4,0,1/4). The Fe magnetic moments with a value of (2.9 ± 0.1) μ(B) are directed at an angle of (78.5 ± 1.8)° to the layers. Application of the magnetic field at T < T(N) induces a metamagnetic phase transition to the ferromagnetic (F) state, which is accompanied by the large magnetoresistance effect (|Δρ/ρ| up to 27%). Below 100 K, the field-induced AF-F transition is found to be irreversible, as evidenced by magnetoresistance and neutron diffraction measurements. The magnetization reversal in the metastable F state is accompanied at low temperatures by substantial hysteresis (ΔH ~ 100 kOe) which is associated with the Ising character of Fe ions.

Substitution Effects on the Magnetic Properties of Fe-Containing Chalcogenides with NiAs-Type Structures

“…2b, the AF-F transition is accompanied by a substantial decrease of the electrical resistivity; the magnetoresistance ∆ρ{ρ pρp0q ¡ ρpHqq{ρp0q reaches -11.5% at 100 kOe, while after switching off the field the magnetoresistance value does not return to its initial value. The inducement of a metastable F state was also evidenced in the Fe 0.5 TiS 2 compound by means of neutron diffraction and magnetoresistance measurements [4,5]. As follows from Fig.…”

“…Bearing in mind the data for the non-substituted Fe 0.5 TiS 2 compound [4,5] the anomaly observed at T 132 K may be associated with the phase transition from the paramagnetic state to the AF order with a non-commensurate magnetic structure which transforms to the commensurate AF structure with further cooling below 85 K.…”

“…According to neutron diffraction both the Fe 0.5 TiS 2 and Fe 0.5 TiSe 2 compounds exhibit an antiferromagnetic (AF) order below 140 K [4,5]. The Fe 0.5 TiS 2 compound was observed to undergo a metamagnetic phase transition from AF to the ferromagnetic (F) state when the magnetic field is applied below T N [5].…”

Соинтеркалация Дихалькогенидов Титана Переходными Металлами И Медью

“…На-пример, интеркалация железом и хромом позволяет формировать сложные магнитные структуры -длин-нопериодические несоразмерные магнитные подрешет-ки и метамагнитные материалы [3,4]. Интеркалация хромом обеспечивает полную спиновую поляризацию состояний на уровне Ферми [5].…”

Pseudobinary Fe4Ti3S8 compound with a NiAs-type structure: Effect of Ti for Fe substitution

“…We have chosen the Fe 4 Ti 3 S 8 composition suggesting that the resultant crystal structure at this Ti amount will contain alternating layers with fully Fe sites and layers of Ti sites with vacancies. Alternating layers of titanium, sulfur and iron were observed in compounds Fe x TiS 2 obtained by intercalation of iron atoms into TiS 2 matrix [11,12]. The parent TiS 2 compound has the CdI 2 -type layered structure in which every other metallic layer in the c direction of the NiAs structure is missing.…”