Hysteresis and vertical anisotropy of magnetoresistance in La0.67A0.33MnOz (A=Ca, Sr) polycrystalline films deposited on amorphous quartz substrates

Polycrystalline La0.67A0.33MnOz (A=Ca, Sr) thin films with [202] preferred orientation were synthesized on amorphous quartz substrates by means of metal organic deposition (MOD) technology. The Curie temperature (TC) and metal−insulator transition temperature (Tp) are 172 K, 247 K and 227 K, 335 K for La0.67Ca0.33MnOz (LCMO) film and La0.67Sr0.33MnOz (LSMO) film, respectively. The hysteresis and vertical anisotropy behaviors of MR are exhibited by the films below TC, which strongly relies on the magnetization process. The magnitude of these magnetotransport properties would decline with increasing temperature. The in-plane hysteric MR behaviors could be explained by multiple-domain model. For vertical anisotropy of MR, demagnetization effect plays an important role. Especially, compared to LCMO film, LSMO film still presents the above hysteretic MR effect and vertical anisotropic MR at RT due to its higher TC.