Giant magneto-resistance estimated from direct observation of nanoscale ferromagnetic domain evolution in La0.325Pr0.3Ca0.375MnO3

Using transmission electron microscopy techniques, we directly imaged the magnetic microstructure of La0.325Pr0.3Ca0.375MnO3 samples as a function of applied field. We measured the domain wall width of two types of domain walls present in the sample, the average domain size, and critical field values for onset and completion of domain wall annihilation. Within an intuitive resistor model, we describe the possible magneto-resistance as a function of applied field at constant temperature and show how local spin inhomogeneities contribute directly to the macroscopic GMR properties. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4749396]