Transport properties and magnetic domain structure in low-doped LaCaMnO manganite single crystals

The low temperature resistivity up-turn in lightly Ca doped LaCaMnO single crystals has been attributed to the domination of the tunneling mechanism in low temperature transport. The intrinsic tunnel barriers have been associated with spontaneous ferromagnetic domains walls. The magneto-optical technique has been employed to observe the relevant domain structure. A regular network of spontaneous ferromagnetic domains undergoes significant changes resulting in apparent rotation of the domain walls in the temperature range coinciding with the resistivity upturn.