Chemical Substitutions in Tl 2 Mn 2 O 7 Pyrochlore,Synthesized Under High Pressure: Effects on the Colossal Magnetoresistance |
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Authors: | P. Velasco J. A. Alonso M. J. Martínez-Lope M. T. Casais J. L. Martínez |
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Affiliation: | 1. C.S.I.C., Cantoblanco , Instituto de Ciencia de Materiales de Madrid , Madrid, E-28049, Spain;2. C.S.I.C., Cantoblanco , Instituto de Ciencia de Materiales de Madrid , Madrid, E-28049, Spain E-mail: ja.alonso@icmm.csic.es |
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Abstract: | Tl 2 Mn 2 O 7 pyrochlore has recently been described as a half-metallic ferromagnet showing colossal magnetoresistance (CMR) properties. New series of Tl 2 Mn 2 O 7 derivatives have been prepared under high pressure conditions. We have replaced Tl 3+ cations by Bi 3+ and Cd 2+ , leading to different modifications of the physical properties, with dramatic improvements of CMR. The Mn 4+ cations have also been partially replaced by Sb 5+ and Te 6+ . In particular, moderate Sb substitution leads to significant increments of T C . In this work we discuss on the effects of the different chemical substitutions on the structural, magnetic and transport properties. |
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Keywords: | Colossal Magnetoresistance Pyrochlores Neutron Diffraction Manganese Oxide Ferromagnetism |
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