No abstract

319Ternary compounds with the general formula are promising for the development of mag netic field controlled lasers, light modulators, ele ments of electric and optical memory, and other opto electronic devices. During the last few years many studies have been devoted to the structural [1], magnetic [2,3], and optical [4][5][6] properties of these crystals. Figure 1 shows the current-voltage (I-V) charac teristics of MnGa 2 Se 4 single crystals. One can clearly see the following stages: (i) a sharp increase in current with an increase in voltage; (ii) sublinear dependence of the current on voltage, (iii) quadratic dependence of the current on voltage, and (iv) a feature that is char acteristic of many high resistivity semiconductors and structures based on them [7][8][9][10][11][12]. When analyzing the I-V characteristics of MnGa 2 Se 4 single crystals mea sured in a wide range of electric fields, the validity of the following conditions was taken into account.Different stages of the I-V characteristics of In-MnGa 2 Se 4 -In structures can clearly be seen in the dependence of the differential exponent α of the I-V characteristic on the applied voltage (I ∝ V α ). Figure 2 shows the dependences α(V) for MnGa 2 Se 4 single crystals, which were determined from the I-V characteristics shown in Fig. 1. It can be seen that α sharply decreases at low voltages, passes through a minimum, and then increases with an increase in voltage to reach a maximum. We will denote the minimum (maximum) differential expo nents as α m (α M ) and the corresponding currents and voltages as I m (I M ) and V m (V M ), respectively. Accord ing to the data in Fig. 2, the extreme values of α, I, and V for the sample with the thickness L = 7 × 10 -3 cm A II B 2 III C 4 VI and the contact area S = 4 × 10 -2 cm 2 at 300 K are as follows:Abstract-The current-voltage characteristics of MnGa 2 Se 4 single crystals have been investigated. The mea surements were performed in the range of electric fields from the level at which the Ohm law is satisfied to 10 V/cm, and in the temperature range 300-400 K. The data obtained are interpreted within the theory of injection-contact phenomena and the theory of field ionization of traps due to the Poole-Frenkel effect.