Strong antiferromagnetic exchange coupling at Gd₂O₃/GdFeO₃ interfaces in nanoparticle ensembles

Signatures of strong antiferromagnetic exchange coupling at the interface of Gd₂O₃/GdFeO₃ subphases of gadolinium nickel zinc ferrite nanoparticle ensemble have been observed. Hybridized domain walls are exchange coupled to the magnetic subphases on both sides of the interface. Origin of the coupling is in the quantum interference of the Bloch waves with the energy states within the domain walls. The coupling mechanism intensifies at low temperatures. A constriction in the middle of the hysteresis loop (at H=0) is believed to be the result of antiferromagnetic transitions which becomes narrow at 5K. The constriction at 5 K effectively divides the hysteresis loop in two parts, confining spin vector components in the positive and negative quadrants. The magnetic susceptibility clearly shows antiferromagnetic transition temperature (T_N) of approximately 17 K.