Evidence of ferromagnetic domains in the La0.67Ca0.33Mn0.9Fe0.1O3 perovskite

The nature of the low-temperature magnetic state of polycrystalline La0.67C a0.33Mn0.9Fe0.1O3 has been studied by magnetization, neutron diffraction, a nd neutron depolarization measurements. Neutron depolarization measurements indicate the existence of ferromagnetic domains with low net magnetic mome nts below 108 K. The substitution of Mn3+ by Fe3+ reduces the number of ava ilable hopping sites for the Mn e(g) (up) electron and suppresses the doubl e exchange, resulting in the reduction of ferromagnetic exchange. The compe tition between the ferromagnetic double-exchange interactions and the coexi sting antiferromagnetic superexchange interactions and its randomness due t o random substitutions of Mn3+ with Fe3+ drive the system into a randomly c anted ferromagnetic state at low temperatures.