Magnetic Hysteresis Behavior Of Granular Manganite La0.67ca0.33mno3 Nanotubes

A silicon micromechanical torsional oscillator is used to measure the hysteresis loops of two manganite La0.67Ca0.33MnO3 nanotubes at different temperatures, applying an external field along its main axes. These structures are composed of nanograins with a ferromagnetic core surrounded by a dead layer. Micromagnetic calculations based on the stochastic Landau-Lifshitz-Gilbert equation are performed to validate a simple model that allows for quantitatively describing the ferromagnetic behavior of the system. Further simulations are used to analyze the experimental data more in depth and to calculate the coercive field, the saturation and remanent magnetizations, and the effective magnetic volume for single nanotubes, over a wide temperature range.