ANASTASIA BURIMOVA
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Resumo IPEN-doc 28750 Local inspection of magnetic properties in GdMnIn by measuring hyperfine interactions2020 - CABRERA-PASCA, G.A.; MAGNO, J.F.; FERREIRA, W.L.; CAMPOS, A.C.; BOSCH-SANTOS, B.; SALES, T.S.N.; PEREIRA, L.F.D.; BURIMOVA, A.; SAXENA, R.N.; FREITAS, R.S.; CARBONARI, A.W.GdMn2 is a member of a series of Laves phase containing a rare-earth element and a magnetic 3dtransition metal with very peculiar magnetic properties[1]. Doping with a non-magnetic element such as indium affects these properties[2,3]. GdMnIn is reported to crystalize in the hexagonal MgNi2-type structure presenting a spin-glass behavior with no magnetic order attributed to the triangular spin frustration of magnetic ions[3]. The observed absence of long-range interactions by magnetization measurements along with the almost impossible measurements with neutron diffraction due to the presence of Gd with very high neutron absorption cross section makes the investigation of local exchange interactions in this compound very difficult. In the present work, measurements of hyperfine interactions at In sites using 111In(111Cd) probe nuclei were carried out by perturbed angular correlations (PAC) technique to investigate the local magnetic exchange in GdMnIn compound. Results displayed in Fig. 1 for the behavior of the major component (Vzz) of the electric field gradient (efg) tensor and the distribution of electric quadrupole frequency () show a strong instability of the electronic environment of In sites when temperature decreases indicating a Mn-In disorder. The weak magnetic hyperfine field at In sites also shown in Fig.1 with an anomalous temperature dependence below around 140 K along with the increase in the angle between Bhf and Vzz directions suggest a weak long-range exchange interaction.Artigo IPEN-doc 27552 Local inspection of magnetic properties in GdMnIn by measuring hyperfine interactions2021 - CABRERA-PASCA, G.A.; MAGNO, J.F.; FERREIRA, W.L.; CAMPOS, A.C.; BOSCH-SANTOS, B.; SALES, T.S.N.; PEREIRA, L.F.D.; BURIMOVA, A.; SAXENA, R.N.; FREITAS, R.S.; CARBONARI, A.W.GdMnIn is reported to crystallize in the hexagonal MgNi2-type structure presenting a spin-glass behavior with no magnetic order attributed to the triangular spin frustration of magnetic ions. In the present work, FC-ZFC magnetization, specific heat and AC susceptibility measurements along with the local magnetic exchange measured by hyperfine interactions at In sites are used to investigate the magnetic behavior in GdMnIn compound. The ZFC-FC magnetization curves exhibit an inflection which was ascribed to the antiferromagnetic transition at TN= 145 K. These curves also give an indication of thermomagnetic irreversibility at 118 K, which along with the absence of inflection in specific heat results might be associated to spin-glass behavior. Results of AC susceptibility and magnetic hyperfine field measured using 111In(111Cd) probe nuclei carried out by perturbed angular correlations (PAC) technique did not show evidence of spin-glass behavior. The thermomagnetic irreversibility in FC-ZFC curves along with results of hyerfine interactions suggest the presence of magneto-crystalline anisotropy effects and a weak long-range coupling in GdMnIn.