IIF-IIR Commissions B2, A1 with E2 Materials 1B3 1 DEVELOPMENT OF MANGANITE MATERIALS FOR ROOM-TEMPERATURE

Manganites of general formula ABMnO3 (where A is a trivalent rare-earth ion and B is a divalent dopant) have interesting properties, namely colossal magnetoresistance and their applicability as materials for active magnetic regenerators. La0.70Sr0.30MnO3 (LSMO) is a ferromagnet presenting considerable magnetocaloric effect, with operating temperature TC~90ºC and magnetic entropy variation comparable to pure Gadolinium. We studied the LSMO system where Lanthanum ions are substituted by Erbium or Europium, effectively lowering the TC to near-room temperature and below. This substitution also increases the relative cooling power (RCP) of the materials, an effect associated to the increased magnetoelastic contribution to the magnetic free energy. These results permit the creation of composites or thermal cascades of chemically similar compounds to produce an active magnetic element with a wide temperature interval of operation (from-40ºC to 90ºC). These materials can be synthesized by solid-state reaction or by sol-gel techniques, and are relati-vely cost-effective