MAGNETIC AND ELECTRICAL-PROPERTIES OF STRAINED (LA0.5SR0.5)COO3 SRTIO3 AND UNSTRAINED (LA0.5SR0.5)COO3/CATIO3 ARTIFICIAL LATTICES/

We have formed strained (La0.5Sr0.5)CoO3/SrTiO3 and unstrained (La0.5S r0.5)CoO3/CaTiO3 artificial lattices, and studied strain-induced magne tic and electrical transport properties of(La0.5Sr0.5)CoO3 layer, comp aring with both films. Only in the strained (La0.5Sr0.5)CoO3/SrTiO3 fi lms: ferromagnetic Curie temperature becomes lower with increasing str ain at the interface by decreasing the stacking periodicity of each la yer. and then spin-glass state emerges at the stacking periodicity bel ow 100 Angstrom. Transport properties change from metallic behaviour t o semiconductive one. These behaviours can be explained by considering that the Co-O bond length is expanded by strain effect so that transf er integral is decreased, leading to the change of magnetic interactio n. (C) 1998 Elsevier Science B.V. All rights reserved.