Itinerant to local transformation and critical point in Ni-rich Ce2(Ni1-yPdy)2Sn alloys

• Main Authors: Sereni, J G, Schmerber, G, M Gómez Berisso, Kappler, J P
• Format: Conference Proceeding
• Language: English
• Subjects: Antiferromagnetism; Critical point; Entropy; Ferromagnetism; Nickel; Physics; Transformations
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/568/4/042029

Structural, magnetic (M) and thermal (Cm) studies on Ce2(Ni1-yPdy)2Sn alloys are presented within the 0 ≤ y ≤ 0.55 range of concentration, showing evidences for itinerant to local electronic transformation. At variance with RKKY type interactions between localized moments μeff, the substitution of Ni by isoelectronic Pd leads the antiferromagnetic transition to decrease from TN 3.8K to 1.2K between y 0 and 0.48, while M(H) measured at H 5T and 1.8K rises from 0.12 up to 0.75μB/Ce-at. Furthermore, the Cm(TN) jump increases with concentration whereas |θP| decreases. The magnetic entropy Sm(T) grows moderately with temperature for y 0 due to a significant contribution of excited levels at low energy, while at y 0.5 it shows a incipient plateau around Sm Rln2. All these features reflect the progressive ground state transformation of from itinerant to a local character. Another peculiarity of this system is the nearly constant value of Cm(TN) that ends in an entropy bottleneck as TN decreases. Consequently, the system shows a critical point at ycr ≈ 0.48 with signs of ferromagnetic behavior above Hcr ≈ 0.3T. A splitting of the Cm(TN) maximum, tuned by field and concentration, indicates a competition between two magnetic phases, with respective peaks at TN ≈ 1.2 K and TI ~ 1.45 K.