Abstract
We report on ac magnetoresistance, R(T,H) and ZFC [MZFC(T)] and FCC [MFCC(T)] dc magnetizations measurements of the a hole doped Y0.9Ca0.1Ba2Cu3O7-δ single crystal with the propose of to disclose the correlation between the zero resistance, TR0(H) and the magnetic irreversibility, Tirr(H) temperatures. The R(T,H) measurements were performed with a PPMS with the measurement current density applied parallel to the sample ab plane. The MZFC(T) and MFCC(T) measurements were performed with a commercial SQUID magnetometer. For the both measurements H ≤ 50kOe were applied parallel to the c axis of the sample. The contrasting of the Tirr(H) and TR0(H) data profile at H-T diagram shows that for H ≤ 5kOe the TR0(H) data falls systematically underneath of the Tirr(H) data and for H > 5kOe the TR0(H) data matches to the Tirr(H) data. We attributed to the establishment of a superconducting granular scenario provided for Ca doping as responsible for the observation of these features. At this scenario, Tirr(H) and TR0(H) do not depend of the same parts of the sample. While the Tirr(H) depends on well coupled grain clusters the TR0(H) depends on grain arrays traversing the whole sample. The granular aspect of this result is discussed at the light of the superconducting glass theories.
Highlights
The magnetic irreversibility of a granular superconductor is characterized by observation of AlmeidaThouless (AT) and Gabay-Toulouse (GT) power laws at low field region of its magnetic irreversibility line (MIL) [1,2,3,4,5,6,7]
In the present work we reported precisely dc magnetization and ac magnetoresistance measurements performed in a hole doped Y0.9Ca0.1Ba2Cu3O7- single crystal with the propose of to disclose the correlation between the zero resistance, TR0(H) and the magnetic irreversibility, Tirr(H)
The results presented at the figures 1A and 1B to the Y(Ca)BCO single crystal are in agreement with those reported from literature to samples well oxygenated of this material [1,2]
Summary
The magnetic irreversibility of a granular superconductor is characterized by observation of AlmeidaThouless (AT) and Gabay-Toulouse (GT) power laws at low field region of its magnetic irreversibility line (MIL) [1,2,3,4,5,6,7]. Otherwise the superconducting resistivity versus temperature transition of a granular superconductor is characterized as a two stage process where the lower temperature one is more affected by the magnetic field [1,2,3]. In a granular scenario magnetic irreversibility, Tirr(H) and zero resistance, TR0(H) temperatures determined from magnetization and resistance measurements respectively are ruled by the physics of superconducting grain coupling [5,7,8].
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