Exploring the Different Degrees of Magnetic Disorder in Tb(x)R(1−x)Cu(2) Nanoparticle Alloys

Recently, potential technological interest has been revealed for the production of magnetocaloric alloys using Rare-Earth intermetallics. In this work, three series of Tb [Formula: see text] R [Formula: see text] Cu [Formula: see text] (R ≡ Gd, La, Y) alloys have been produced in bulk and nanoparticle sizes via arc melting and high energy ball milling. Rietveld refinements of the X-ray and Neutron diffraction patterns indicate that the crystalline structure in all alloys is consistent with TbCu [Formula: see text] orthorhombic [Formula: see text] bulk crystalline structure. The analyses of the DC-magnetisation ([Formula: see text]) and AC-susceptibility ([Formula: see text]) show that three distinct degrees of disorder have been achieved by the combination of both the Tb [Formula: see text] replacement (dilution) and the nanoscaling. These disordered states are characterised by transitions which are evident to [Formula: see text] , [Formula: see text] and specific heat. There exists an evolution from the most ordered Superantiferromagnetic arrangement of the Tb [Formula: see text] La [Formula: see text] Cu [Formula: see text] NPs with Néel temperature, [Formula: see text] 27 K, and freezing temperature, [Formula: see text] 7 K, to the less ordered weakly interacting Superparamagnetism of the Tb [Formula: see text] Y [Formula: see text] Cu [Formula: see text] nanoparticles ([Formula: see text] absent, and T [Formula: see text] 3 K). The Super Spin Glass Tb [Formula: see text] Gd [Formula: see text] Cu [Formula: see text] nanoparticles ([Formula: see text] absent, and [Formula: see text] 20 K) are considered an intermediate disposition in between those two extremes, according to their enhanced random-bond contribution to frustration.