Neutron scattering evidence for magnetic-field-driven abrupt magnetic and structural transitions in a phase-separated manganite

[摘要] Substitutions at the Mn site of the charge-ordered Pr0.5Ca0.5MnO3 manganite is an effective way to induce abrupt jumps on the magnetic-field-driven magnetization curve. In order to get new insights into the origin of this remarkable feature, the Pr0.5Ca0.5Mn0.97Ga0.03O3 perovskite manganite has been studied by neutron diffraction versus temperature and at 2.5 K in an applied magnetic field up to 6 T. A weak and complex antiferromagnetic order is found for the low-temperature ground state. Magnetic transitions, associated with structural ones, are evidenced for certain strengths of magnetic field, which gives rise to the steplike behavior corresponding to the magnetization curve. Small-angle neutron scattering provides evidence for a nucleation process of micron-size ferromagnetic domains which follows the magnetization behavior.

[发布日期] 2003-12-01

[关键词] ORBITALLY ORDERED MANGANITES;METAMAGNETIC TRANSITIONS;CHARGE;DIFFRACTION;CR;STATE