We have essentially widened the capabilities of the open-flat coil-based tunnel diode oscillator technique (OFC magnetometer) for simultaneous tests of magnetic penetration depth, λ, of rf magnetic field and for detection of small changes of absorption inside the thin plate-like HTS materials. The updated method is based on simultaneous detection of the inductance and Q-factor value changes of the unusual flat (single-layer open-faced geometry) coil-based MHz-range resonator, which finally leads to the resonant frequency and amplitude changes of the oscillator. Our technique enables detecting the changes ∼10-12 H of HTS film's magnetic inductance (the changes ∼1-3 Å of λ). It detects also the changes ∼10-9 W of testing field's power absorption by the film, originated from the variation of its internal flux distribution (due to vortex flow during the suppression of superconductivity by external magnetic field). It can operate in wide ranges of temperature and magnetic field and measure in wide dynamic ranges of the testing parameters. We present the test results of the 0.2 μm thick and a few millimeter in diameter disk- and ring-shaped YBaCuO films illustrating wide capabilities of the updated OFC magnetometer to study weakly expressed peculiarities of superconductive state related, in particular, with the insignificantly small absorption at vortex motion.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering