New paramagnetic peculiarity of the superconductive transition detected by a highly sensitive OFC magnetometer

Abstract

The improved `LC-resonator' technique (the open-flat coil magnetometer), based on a low-power stable-frequency tunnel diode oscillator with a single-layer open-faced coil, is very sensitive to changes of position. About 1 Å absolute and better than 10-6 relative resolution can be reached in distance change measurements. It is an excellent MHz-range scientific instrument with which one may study weakly expressed fine peculiarities of the superconductive state in small-volume thin plate-like high-Tc superconductors (HTS). It enables changes to be detected of about 1 pH of the HTS film's magnetic inductance (changes of ~1-3 Å of the magnetic penetration depth, λ) with very high (~10-6) relative resolution. Owing to the pick-up coil's flat design, relatively low operation frequency and high relative resolution, the present method has advantages over others. It is essential for non-destructive studies of thin flat HTS materials (with a small signal) especially near Tc (at the beginning of the formation of `Cooper' pairs). Mainly as the result of these advantages a new `paramagnetic' peculiarity of the superconductive transition has been detected in Y-Ba-Cu-O film, which precedes the well known `diamagnetic' ejection. A possible explanation of the observed effect is given, and the influence of some external physical parameters on the effect is revealed and discussed.

Complicated shape of the superconductive transition curve revealed by a sensitive OFC-magnetometer

“…That's why we could detect recently a weakly expressed new 'Para-Magnetic' peculiarity of superconductive transition in YBaCuO film (retraction of a testing MHz-range field) before its 'Dia-Magnetic' ('Meissner') ejection [12], shown in Fig. 1(a).…”

A single-layer flat-coil-oscillator (SFCO)-based super-broadband position sensor for nano-scale-resolution seismometry

“…Besides, due to the flat shape even small shift of the position of a normal-conducting plate, placed near the coil, may lead to a strong distortion of the field distribution around the coil. These features and the stability of TD oscillators (DF stab $2À10 Hz, DF/F$10 À6 À10 À7 -depending on model and temperature [8][9][10]) enabled us to reach 6 orders relative resolution in the SFCO technique [2,3], permitting to detect weakly expressed effects in high-T c superconductive (HTSC) materials [5,6,11].…”

Newly-Proposed Methods for Early Detection of Incoming Earthquakes, Tsunamis & Tidal Motion

“…It can be used for determination of too much little changes of distances with d~1-10Å absolute and d/d~10  5 -10  6 relative resolution (depending on a model and working temperature of the TD-oscillator [3][4]. It is also a sensitive radio-frequency (RF) Q-meter  to study absorption as small as 10  9 W in thin flat materials (for example, in plate-like high-T c superconductors [5][6][7]). The SFCO method can operate down to the liquid 4 He temperatures.…”

“…Besides, due to flat shape, even a little shift of the position of a normal-conducting plate, placed near the coil, may www.intechopen.com lead to strong distortion of the field distribution around the coil. These features, and the stability of TD-oscillators (F stability 1-10Hz, F/F10  7 -10  6  depending on the model & temperature  see [2,[11][12]) enabled us to reach 6 orders relative resolution in SFCO technique [3][4], permitting to effectively use it in a basic research [5][6][7][8], as well as in some modern technical applications [9][10]. In the last case, frequency of the oscillator is mainly used as a testing parameter, and the measuring effect is determined by a distortion of the MHz-range testing field configuration near the coil face by the vibrating copper plate, leading to the magnetic inductance changes of the coil, with a resolution  1-10pH (depending on operation temperature of a technique), resulting in the changes of test oscillator frequency.…”

“…ment of the resolution of measurements by 3-4 orders of magnitude (especially, in studies of thin, plate-like HTS materials [1,[3][4][5][6][7][8]). For comparison, typical values of the filling factor for solenoid coils are 10  4 10  3 for the said samples.…”