Magnetoresistance in (La1−xCax) MnO3 films

Abstract

Thin films of (La1−xCax)MnO3 with 0 ≤ X ≤ 1 have been prepared by pulsed laser deposition. Films with x = 0.3 and 0.5 which are in the composition range for ferromagnetism show an increased resistance and a giant magnetoresistance effect around the Curie temperature. In the case of x = 0.3, the resistance falls from 50 mΩ cm at Tc to 400 μΩ cm as T → 0 K. There is also a large magnetoresistance effect around the Curie point (Δρ/ρ0 = 80% in 5 T), which persists for x = 0.5 to low temperatures. These results are interpreted in terms of the magnetic polaron transport in the imperfectly ordered ferromagnetic material.