Low-field phenomenology and characteristic lengths of hydrogen- and halogen-doped YBa sub(2)Cu sub(3)O sub(7- delta ) compounds

• Published in: Journal of low temperature physics Vol. 116; no. 5; pp. 407 - 419
• Main Authors: Dehmej, J, Fouad, Y, Burin, J P, Peyral, P, Rosenblatt, J, Lebeau, C, Raboutou, A, Massiot, P, Perrin, C, Korn, C, Goren, S D
• Format: Journal Article
• Language: English
• Published: 01-01-1999
• Subjects: Ceramic materials; Diamagnetism; Halogen elements; Hydrogen; Phase transitions; Temperature
• ISSN: 0022-2291

We measure the diamagnetic response of YBa sub(2)Cu sub(3)O sub(y)A sub(x) (A identical with Cl, F, H) ceramics. We obtain low-field effective penetration depths lambda of a few 10 mu m, first flux-penetration field H sub(1) distinguishable from the volume penetration field H sub(C1) and two characteristic temperatures T sub(s) and T sub(c), T sub(c) < T sub(s), defined by the onset of the real and imaginary parts of the susceptibility, respectively. H sub(1)(T) goes to zero as a power law H sub(1)(T, x) identical with H sub(1)(0, x) (T - T /T sub(c)) super(2.7) near T sub(C). From the values of lambda and H sub(1) we infer the correlation length xi at T identical with 4.2 K. A large range of values for xi (4.2) suggests that chemical disorder plays an essential role in the phenomenology of cuprates. We find lambda (4.2) - H sub(1)(4.2) super(-1/3). This, and the power law xi (4.2) - H sub(1)(4.2) super(-2/3) result from the scaling properties of a phase transition governed by disorder.