Sign Reversal of anisotropic magnetoresistance in La0.7Ca0.3MnO3/STO   ultrathin films
  We present the observation of strain induced sign reversal of anisotropic magnetoresistance (AMR) in LCMO (LCMO) ultrathin films (thickness 4 nm) deposited on STO (001) substrate (STO). We have also observed unusually large AMR in LCMO/STO thin films with thickness of 6 nm below but close to its Curie temperature (TC) which decrease as the film thickness increases. The sign reversal of AMR (with a maximum value of - 6) with magnetic field or temperature for the 4 nm thin film may be attributed to the increase in tensile strain in the plane of the thin film which in turn facilitates the rotation of the magnetization easy axis. 
Himanshu Sharma, A. Tulapurkar, C. V. Tomy
cond-mat.mes-hall cond-mat.mtrl-sci