Contribution to the study of domains and magnetic phenomena by new recordings: "Magnetic neutron Laue diffraction"

The paper describes recent experimental work which shows that the Laue method for recording magnetic neutron diffraction micrographs is able to reveal individual domains simultaneously in poly-domain crystals of nickel oxide. Not only can the positions of the domains be seen by white beam magnetic neutrographs of the sample but also the population of small magnetic domains like in synthetic hematite are determined by a not too sophisticated instrumental procedure. The magnetic neutron Laue diffraction (MNLD) method provides a new tool for magnetism. To illustrate this, data were obtained to i) determine domain distribution versus the field orientation in hematite and ii) observe antiferromagnetic viscosity of S-walls in nickel oxide. We can foresee new topics to be studied by this new method as complex magnetic structures and phase transitions.