Article comprising improved magnetoresistive material

摘要

An article comprising a first material that exhibits magnetoresistance and comprises La, Ca, Mn and O with a derivative (dp/dH) at a given value of applied field H and temperature T where p is the electrical resistivity. The material comprises a further constituent selected from Sr, Ba and Sr/Ba at an amount selected to provide the first material at a value of H /~ 0.05 Tesla and 25 deg C with a value of (dp/dH) that is at least twice the value in the absence of the further constituent.