Magnetism and superconductivity in La_1.875Ba_0.125-ySr_yCuO_4+\delta and La_1.6-yNd_0.4Sr_yCuO_4

Authors: Lappas A.¹; Cristofolini L.¹; Prassides K.¹; Vavekis K.¹; Amato A.²; Gygax F.N.²; Pinkpank M.²; Schenck A.²

Source: Hyperfine Interactions, Volume 105, Numbers 1-4, 1997 , pp. 101-106(6)

Publisher: Springer

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Abstract:

^+SR and neutron diffraction measurements show that at low temperatures in La_1.875 Ba_0.125 CuO_4, there is phase separation into a long range ordered magnetic component of SDW-like nature, identified with the LTT phase and a superconducting component, identified with the LTO phase. Partial substitution of Ba by Sr at a fixed doping level of 1/8 leads to gradual decrease of the magnetic freezing temperature, accompanied by a decrease in the fraction of the magnetic component. The La_1.875 Ba_0.025 Sr_0.100 CuO_4 composition exhibits freezing of the Cu electronic moments into a disordered arrangement. Excess interstitial oxygen leads to a rapid recovery of superconductivity and a marked depression of the magnetic volume fraction. Study of the LTT phase – after stabilisation with partial substitution of La by Nd – away from the 1/8 doping level, reveals no evidence of long range magnetic ordering with magnetic fluctuations surviving down to 3 K.

Language: English

Document Type: Regular paper

Affiliations: 1: School of Chemistry and Molecular Sciences, University of Sussex, Brighton BN1 9QJ, UK 2: Institute for Particle Physics, ETH Zürich, CH-5232 Villigen PSI, Switzerland

Publication date: 1997-01-01