Proximity induced metal-insulator transition in YBa2Cu3O7/La2/3Ca1/3MnO3 superlattices

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Authors	HOLDEN Todd HABERMEIER Hanns CRISTIANI Georg GOLNIK Andrzej BORIS Alexander PIMENOV Alexei HUMLÍČEK Josef
Year of publication	2004
Type	Article in Periodical
Magazine / Source	Physical Review B
MU Faculty or unit	Faculty of Science
Citation
Field	Solid matter physics and magnetism
Keywords	SPECTROSCOPIC ELLIPSOMETRY; SYNCHROTRON-RADIATION; ANISOTROPIC MEDIA; SUPERCONDUCTIVITY; MAGNETORESISTANCE; HETEROSTRUCTURES; FERROMAGNETISM; RUSR2GDCU2O8; COEXISTENCE; MAGNETISM
Description	The far-infrared dielectric response of superlattices (SL) composed of superconducting YBa2Cu3O7 (YBCO) and ferromagnetic La0.67Ca0.33MnO3 (LCMO) has been investigated by ellipsometry. A drastic decrease of the free-carrier response is observed which involves an unusually large length scale of d(crit)approximate to20 nm in YBCO and d(crit)approximate to10 nm in LCMO. A corresponding suppression of metallicity is not observed in SL's where LCMO is replaced by the paramagnetic metal LaNiO3. Our data suggest that either a long-range charge transfer from the YBCO to the LCMO layers or alternatively a strong coupling of the charge carriers to the different and competitive kind of magnetic correlations in the LCMO and YBCO layers is at the heart of the observed metal-insulator transition. The low free-carrier response observed in the far-infrared dielectric response of the magnetic superconductor RuSr2GdCu2O8 is possibly related to this effect.
Related projects:	Physical properties of new materials and layered structures