Magnetic Properties of FeSeTe Compound Crystallized from Liquid Phase

Abstract

We report on measurements of samples with nominal composition FeSe 0.5 Te 0.5 , crystallized by the Bridgman method. Magnetic and transport properties of the samples were examined. The measurements confirm the coexistence of ferromagnetism and superconductivity below the superconducting transition temperature. The ferromagnetic contribution to magnetization, estimated at 10%, might be caused by the presence of ferrimagnetic Fe7Se8, which occupies about 10% of sample volume. From the Andreev spectroscopy we found superconducting energy gap ∆ = 2.6 meV at T = 4.2 K, and from magnetization measurements the critical temperature Tc = 15.8 K.The critical current density in magnetic field H = 4 kOe, determined from magnetization measurements, is jc = (1-2) × 10 4 A/cm 2 and weakly depends on magnetic field intensity.

Synthesis of Bulk FeTe1−x Se x (x = 0.1−0.5) at Ambient Pressure

“…Apparently, all the samples exhibit ferromagnetism consistent with previously reported literature [32,36,37]. The ferromagnetic behavior has been suggested to be contributed by the ferromagnetic nature of Fe [38] and the existence of a small amount of magnetic impurities such as Fe 3 O 4 [29] or Fe 7 Se 8 which is a magnetically ordered compound at room temperature [37][38][39]. As shown in Fig.…”

A new approach for improving global critical current density in Fe(Se0.5Te0.5) polycrystalline materials

“…The iron chalcogenides (11 phase), as compared to the other iron superconductors, present the lowest T c (9-15 K) and rather low critical current densities in self-field, in the range of 10 4 -10 5 A cm −2 for single crystals [6,18,19], and several times 10 5 A cm −2 for thin films [20]. However, the huge upper critical field and the consequent weak dependence of J c on the field [21], together with the simple structure and the lack of poisonous elements, all contribute in making the 11 phase particularly attractive for high-field applications.…”