Radicals as EPR probes of magnetization of gadolinium stearate Langmuir–Blodgett film

In the present work we have applied the method of the EPR spin probes which allows performing simultaneously EPR and magnetization measurements to the investigation of magnetism of the Gd stearate Langmuir–Blodgett (LB) films. For this purpose we have prepared and studied by the EPR technique the Gd and Y stearate LB films. Placing the small BDPA crystal on the film surface we have found that for the Gd LB sample the effective g-value of the radicalʹs resonance depends on the film orientation in respect to the external magnetic field direction. The relative shift of the EPR signal corresponded to the magnetization of the film along the field direction. Such effect has not been observed for the Y stearate LB film. The data obtained give an experimental proof for the room temperature magnetic ordering in the gadolinium stearate LB film.