Low-Field Magnetoresistance in La0.67Sr0.33MnO3:ZnO Composite Film

A nanocomposite film of La0.67Sr0.33MnO3 (LSMO):ZnO is synthesized by depositing LSMO solution on a vertical array of ZnO nanorods grown on (0001) Al2O3 substrate. The magnetic behavior of the composite film differs from that of a pure LSMO film, possibly due to smaller grain size in the composite, small amount of Zn doping, or the presence of nonmagnetic ZnO phase near the LSMO grain boundaries. Magnetotransport measurements show that the low‐field magnetoresistance (LFMR) of the nanocomposite film is significantly enhanced as compared to that observed for pure LSMO film. The highest value of the LFMR of the nanocomposite film at 10 K is –23.9% with a magnetic field of 0.5 T applied parallel to the current. A La0.67Sr0.33MnO3:ZnO composite film is fabricated by spin‐depositing a La0.67Sr0.33MnO3 phase in between ZnO nanorods hydrothermally grown on a (0001)‐Al2O3 substrate. This unique nanocomposite fabrication method results in an enhanced low‐field magnetoresistance effect that is believed to be due to spin polarized tunneling through modified La0.67Sr0.33MnO3 grain boundaries in the composite film.