Chemical-pressure tailoring of low-field, room-temperature magnetoresistance in (Ca, Sr, Ba)Fe0.5Mo0.5O3

Low-field intergrain magnetoresistance (IMR) in the polycrystalline materia ls of double perovskite SrFe0.5Mo0.5O3 is found to be highly tunable by dop ing either Ca or Ba into the Sr site. The dopant exerts a chemical pressure , changing the Curie temperature and the magnetic softness. The room-temper ature IMR at optimal doping (Sr0.2Ba0.8Fe0.5Mo0.5O3) is approximately 3.5% in 100 Oe, and increases further in high fields. The unprecedented magnitud e of the IMR in this highly spin polarized system provides future grounds f or employing magnetic materials for innovative magnetic technology. (C) 200 1 American Institute of Physics.