Paramagnetic Meissner effect in YBa2Cu3O7-δ: a non-resonant microwave absorption study

Bhat, S. V. ; Rastogi, A. ; Kumar, N. ; Nagarajan, R. ; Rao, C. N. R. (1994) Paramagnetic Meissner effect in YBa2Cu3O7-δ: a non-resonant microwave absorption study Physica C: Superconductivity, 219 (1-2). pp. 87-92. ISSN 0921-4534

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Official URL: http://www.sciencedirect.com/science/article/pii/0...

Related URL: http://dx.doi.org/10.1016/0921-4534(94)90018-3

Abstract

The low-field dependence of non resonant microwave absorption (MWA) in polycrystalline samples of YBa2Cu3O7-δ with 0.1≤δ≤0.5 has been measured at T < Tc along with simultaneous monitoring of paramagnetic impurities in the chain copper (Cu-I) sites by EPR spectroscopy. MWA exhibits a cross-over from the normal zero-field minimum to an anomalous zero-field maximum accompanied by the gradual appearance and growth of the EPR signal as δ is changed from 0.1 to 0.5. It is to be noted that in the δ = 0.3-0.4 composition range, oxygen vacancies are disordered giving rise to magnetic moments due to isolated Cu2+ impurity ions. This correlation of the anomalous MWA with isolated paramagnetic Cu2+ impurities is consistent with the presence of π junctions, earlier implicated in the paramagnetic Meissner effect (PME), which in turn is related to the anomalous MWA.

Item Type:Article
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ID Code:85126
Deposited On:29 Feb 2012 13:42
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