Tunel Diode Oscillator


Radio frequency measurement technique based on tunnel diode oscillator (TDO) is very useful for the investigation of transport properties of metalic samples with small resistance or /and where low contact-resistance cannot  be achieved.

The device is a LC-tank circuit powered by a tunnel diode biased in the negative resistance region of the current-voltage characteristic. The resistivity variation of the metallic sample leads, at first order, through skin depth variation (∆δ), to change in coil inductance. The resulting variation of the oscillator frequency can therefore be regarded as proportional to resistivity variations.

As an example we show quantum oscillations obtained in the organic conductor κ-(BEDT-TTF)2Cu(NCS)2 measured with torque magnetometry (blue) and with TDO method (green). More detailed example can be found here.

Pulsed field Static field
Bmax 90 T 36 T
Temperature range 0.5 K - 300 K 1.2 K - 300 K