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- Title
Evidence of re-entrant spin-glass behavior in the GdAgGa compound.
- Authors
França, J. K. P.; dos Reis, D. C.; Fabrelli, H.; Bittar, E. M.; dos Santos, A. O.; da Silva, L. M.
- Abstract
Structural, magnetic, calorimetric, and magnetocaloric properties of the GdAgGa polycrystalline intermetallic compound are reported. This compound crystallizes with an orthorhombic CeCu2-type structure. Magnetization data reveal a phase transition from a paramagnetic to a ferromagnetic state around Curie temperature (TC) = 30 K and a low-field-dependent anomaly (T*) below 14 K. Features on the time dependence of magnetic relaxation, thermomagnetic irreversibility below T*, absence of a λ-type peak on zero-field heat capacity, and the frequency dependence of imaginary and real components of ac susceptibility indicate a complex magnetic structure, in which a re-entrant spin-glass (RSG) phase coexists with long-range ferromagnetism. The RSG phase arises due to the nonmagnetic atom disorder, which induces a non-uniform ferromagnetic phase. As temperature decreases, such non-uniformity contributes to the development of spin-glass correlation. The applied external magnetic field destabilizes the RSG phase, and the magnetization increases reaching ~ 6.1 µB per Gd ion at T = 2 K for a magnetic field of 50 kOe. Isothermal magnetic entropy change (ΔSM) exhibits a broad curve with its maximum around TC and a long tail over a wide temperature range above TC. The inverse magnetocaloric effect (MCE) for T < 10 K is consistent with antiferromagnetic interactions from the RSG phase. An appreciated magnetic entropy change was observed with a maxima value of ~ 7 J/kg K and a relative cooling power of 264 J/kg for a magnetic field change of 50 kOe. The nature of the magnetic state is a critical factor influencing the GdAgGa compound magnetocaloric effect.
- Subjects
MAGNETIC entropy; MAGNETIC structure; MAGNETOCALORIC effects; PHASE transitions; MAGNETIC fields; CURIE temperature
- Publication
Applied Physics A: Materials Science & Processing, 2023, Vol 129, Issue 6, p1
- ISSN
0947-8396
- Publication type
Article
- DOI
10.1007/s00339-023-06719-6