K. M. Aliev

N-shaped voltage-current characteristic and current oscillations in Sm1−x SrxMnO3 manganite

The voltage-current characteristics (VCC) of Sm1−xSrx MnO3 samples with x=0.425 and x=0.450 were experimentally studied at a temperature of 77 K in pulsed and constant electric (E) and magnetic (H) fields up to 10 kOe for the H‖E and H⊥E orientations. N-shaped VCCs and high-frequency (up to 3 MHz) current oscillations were observed. It was found that the effect of colossal magnetoresistance had a threshold character and was smoothly reduced to zero with E→0.

Absolute negative resistance and multivaluedness on current-voltage characteristics of tunnel diodes

The effect of external perturbations of large amplitude in the form of a coherent signal or noise on the behavior of dynamic and static current-voltage (I–V) characteristics of tunnel diodes has been experimentally investigated. It is shown that, when an appropriate frequency is chosen, an increase in the amplitude of the external coherent signal leads to the occurrence of multivaluedness and absolute negative resistance on the I–V characteristics of tunnel diodes. The noise effect suppresses the N-type negative differential resistance on the I–V characteristics of tunnel diodes and significantly distorts these characteristics. A possible mechanism of the occurrence of absolute negative resistance is proposed.

Stepwise current oscillations in tunnel and high-frequency semiconductor diodes

The response of tunnel and high-frequency diodes to an external harmonic signal of large amplitude has been studied. Stepwise current oscillations have been found on the current-voltage characteristics measured at a direct current when an external high-frequency signal is imposed simultaneously on the sample. The frequency of these oscillations decreases with increasing frequency of the external signal. Analogs of the appearance of stepwise current oscillations in semiconductor and other systems are indicated.

Conductivity of semiconductor diodes with simultaneously applied direct and alternating biases

The influence of a high-amplitude high-frequency signal on the static current-voltage characteristics of commercial semiconductor p-n junction diodes is studied experimentally. S-shaped regions are observed in the direct branches of the current-voltage characteristics over a wide frequency range, and a bell-shaped segment is seen in the reverse branches. The value and position of the latter on the voltage axis considerably depend on the alternating signal frequency.

N-type negative differential resistance, hysteresis, and oscillations in the current-voltage characteristics of microwave diodes

The dc current-voltage characteristics of microwave diodes are experimentally studied on simultaneous exposure of the diodes to a high-frequency (100 MHz) high-amplitude harmonic signal. In the current-voltage characteristics of the microwave diodes, regions of N-type negative differential resistance, hysteresis, and current oscillations are observed depending on the amplitude and frequency of the high-frequency signal. A comparative analysis of the experimentally observed effects is performed, and possible mechanisms for the effects are discussed.

Synchronization of chaos and small signal amplification in electron-hole plasma of germanium

The effect of an external harmonic signal on the screw instability of the current in the electron-hole plasma has been studied experimentally in Ge at 77 K and 300 K. The influence exerted by external signals with various amplitudes and frequencies, applied to a sample both additively and multiplicatively, on the synchronization, amplification and stability of the system in absolute and convective modes of instability excitation has been investigated at points of bifurcation in a wide region of the parametric space.

Chaos in germanium oscillistor

Dynamic chaos evolution scenarios of the development of a Kadomtsev-Nedospasov instability in the electron-hole plasma in germanium at 77 and 300 K have been studied experimentally in external electric and magnetic fields at high control parameters. The development of a spatio-temporal chaotic state in the system has been analysed using probe measurements along a sample. It is shown that several attractors, with their own dimensions and power characteristics, may exist simultaneously in the same sample. Scenarios have been found leading to chaos through period doubling, quasi-periodicity and intermittency, depending on the parametric space; transitions of the order-chaos-order type have also been observed.

Negative differential conductivity and recombination instability of current in p-Ge(Au) in two-parametric space

We present the results of an experimental study of p-Ge(Au) samples and we compare these qualitatively with data furnished by the one-dimensional theoretical model developed to account for the recombination instability in gold-doped germanium in the two-parametric space, with voltage (V) and emission (β) as parameters. A second portion with S-switching is revealed in the current–voltage characteristics.

A magnetic field sensor based on the mechanoelectric effect in semiconductors

A highly sensitive magnetic field transducer based on the mechanoelectric effect in semiconductors is proposed.

The Feigenbaum—Sharkovskii—Magnitskii scenario of transition to chaos in a circuit with a tunnel diode

The scenarios of transition to a chaotic state in a circuit with a tunnel diode are experimentally studied. It is shown that there are regions on the plane of control parameters where the Feigenbaum scenario and the Sharkovskii order alternate and chaos is reached through intermittency.