Isothermal magnetization curves above the transition temperature T c in a single crystal of superconducting underdoped cuprate La 1.9Sr0.1CuO4 are reported. In the low-field range, H≤1kOe, and for T within Tc -2 K, evidence is given of a fluctuating diamagnetism different from the one expected from the Ginzburg-Landau theory in finite fields. The experimental findings are related to phase fluctuations of order parameter in "droplets" having local Tcloc higher than the bulk resistive Tc, a general phenomenon in cuprates and intrinsic consequence of charge inhomogeneities at mesoscopic level. The temperature dependence of the droplets size suggests a percolative character of the transition.
On the character of the fluctuating diamagnetism above the superconducting transition in La1.9Sr0.1CuO4 / A. Lascialfari, A. Rigamonti, L. Romanò, A. Varlamov, I. Zucca. - In: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS. - ISSN 0304-8853. - 272:Suppl. 1(2004), pp. E1071-E1072.
On the character of the fluctuating diamagnetism above the superconducting transition in La1.9Sr0.1CuO4
A. Lascialfari;
2004
Abstract
Isothermal magnetization curves above the transition temperature T c in a single crystal of superconducting underdoped cuprate La 1.9Sr0.1CuO4 are reported. In the low-field range, H≤1kOe, and for T within Tc -2 K, evidence is given of a fluctuating diamagnetism different from the one expected from the Ginzburg-Landau theory in finite fields. The experimental findings are related to phase fluctuations of order parameter in "droplets" having local Tcloc higher than the bulk resistive Tc, a general phenomenon in cuprates and intrinsic consequence of charge inhomogeneities at mesoscopic level. The temperature dependence of the droplets size suggests a percolative character of the transition.Pubblicazioni consigliate
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