AC electrical properties of FeIn2S4

Abstract

FeIn 2 S 4 belongs to the ternary compounds of class AB 2 X 4 (where A = Mn, Fe, Co, Ni; B = Ga, In; and X = S, Se, Te) some of which are being extensively studied today [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. These compounds are promis ing for lasers, light modulators, photodetectors, and other magnetically controlled functional devices.The physical properties of FeIn 2 S 4 were studied in [1][2][3][4][8][9][10][11][12]. Specifically, the structure and magnetic properties of FeIn 2 S 4 were investigated in [1,4]. It was found that this compound is antiferromagnetic at tem peratures below Néel temperature T N = 4.2 K. In [8], the electrical properties of FeIn 2 S 4 in a static field were explored and the switching effect was discovered. Works [9,10] were devoted to the electrochemical properties of FeIn 2 S 4 nanocrystals. In [11,12], FeIn 2 S 4 based photosensitive structures were fabri cated. However, the ac properties of this compound have not been touched upon. In this work, we report experimental data for the ac electrical performance of FeIn 2 S 4 .FeIn 2 S 4 polycrystals were obtained by direct alloy ing of high purity (99.99%) elements taken in stoichi ometric amounts. It was found by the X ray diffraction method that the polycrystals have a spinel structure with lattice parameter a = 10.62 Å [1, 3]. The electri cal properties were measured on ~0.5 mm thick wafers cut from a FeIn 2 S 4 ingot on which silver paste electrodes (plates) were applied. The capacitors thus obtained were placed in a thermostat, where the tem perature was controllably varied between 293 and 400 K. The temperature was measured accurate to ±0.5 K. The capacitance and resistivity were measured with E7 20 digital immitance meters (frequency range 25-10 6 Hz). The measuring voltage applied to the sample was 1 V. Figure 1 plots capacitance C of the capacitor with FeIn 2 S 4 semiconductor inside versus frequency f at different temperatures. Permittivity ε was calculated from the formula .It was found that ε varies within 300-2800 in the temperature interval 293-373 K and the frequency range 5 × 10 3 -10 6 Hz. It is seen in Fig. 1 that, at tem peratures between 293 and 323 K, the capacitance first slowly decreases in the frequency range 5 × 10 3 -2 × 10 5 Hz and then, in the frequency interval 2.5 × 10 5 -5.0 × 10 5 Hz, a resonance is observed. As the temper ature rises further, the resonance disappears. The res onance effect can be explained in terms of the barrier model [17], since imperfect crystals may contain, along with high resistivity layers with local barrier grains, extended low resistivity barrier layers localized on inhomogeneities, such as dislocations, electrical C εε 0 S/d = Abstract-The frequency and temperature dependences of the ac capacitance and resistivity of FeIn 2 S 4 semiconductors are studied. Resonances are observed at certain temperatures in the frequency range (2.5-5.0) × 10 5 Hz. The permittivity of the crystals and the activation energy of charge carriers are determined. It is found that elec...

FeS–FeGaInS4–FeIn2S4 SYSTEM

“…It is known that the development of a new scientific fieldspintronics is associated with the possibility of transferring the oriented electron spin from a ferromagnet to a semiconductor. The above compounds also apply to materials promising for the specified area [9][10][11]. MnBi 2 Te 4 (the first antiferromagnetic topological insulator) MnBi 4 Te 7 and MnBi 6 Te 10 compounds were described in papers [12][13][14][15] publicshed recently.…”