Magnetic relaxation in an isotropic extreme type-II superconductor

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.2735· OSTI ID:5887186

Svedlindh, P; Niskanen, K; Norling, P; Nordblad, P; Lundgren, L ^[1]; Rossel, C ^[2]; Sergent, M; Chevrel, R; Potel, M ^[3]

---

1. Uppsala University, Institute of Technology, Box 534, S-751 21 Uppsala, Sweden (SE)
2. IBM Research Division, Zuerich Research Laboratory, 8803 Rueschlikon (Switzerland)
3. Chimie Minerale B, Universite de Rennes, 35042 Rennes CEDEX (France)

The time dependence of the zero-field-cooled and thermoremanent magnetization of the isotropic extreme type-II superconductor PbMo{sub 6}S{sub 8} has been measured at temperatures 0.7{le}{ital T}/{ital T}{sub {ital c}}{le}0.95 and for fields 1{le}{ital H}{le}300 G. The results show that the time dependence of the decay can be divided into three different field regimes: (1) A low-field regime with a closely logarithmic decay and a well-established critical state. The relaxation rate ({partial derivative}{ital M}/{partial derivative} ln({ital t})) increases as {ital H}{sup 5} for the zero-field-cooled magnetization and as {ital H}{sup 2.4} for the thermoremanent magnetization. The reduction in magnetization over 5 decades in time (0.3--3{times}10{sup 4} s) is, at most, a few percent. (2) A crossover-field regime with a change from a logarithmic to a nonlogarithmic decay. (3) A high-field regime where the time dependence of the decay is well described by the expression {delta}{ital M}{similar to}(ln({ital t}/{tau}{sub 0})){sup {minus}{alpha}}. The reduction in magnetization in the crossover- and high-field regimes is as large as 25--30 % in the measured time interval. The results in the high-field regime are interpreted within the theory of collective flux creep. Comparisons are made with the magnetic relaxation found in anisotropic high-{ital T}{sub {ital c}} superconductors.

• OSTI ID: 5887186
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:4; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
CHALCOGENIDES
DECAY
LEAD COMPOUNDS
LEAD SULFIDES
MAGNETIC FIELDS
MAGNETIZATION
MOLYBDENUM COMPOUNDS
MOLYBDENUM SULFIDES
REFRACTORY METAL COMPOUNDS
RELAXATION TIME
SULFIDES
SULFUR COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TYPE-II SUPERCONDUCTORS