Magnetism in gallium-dopedCeFe2: Martensitic scenario

Abstract

Ce͑Fe 1−x Ga x ͒ 2 compounds with x = 0, 0.01, 0.025, and 0.05 have been investigated to unravel the effect of Ga on the magnetic state of CeFe 2 . We find that the dynamic antiferromagnetic phase present in CeFe 2 gets stabilized with Ga substitution. The hysteresis loops show that while the compounds with x = 0 and 0.01 show normal ferromagnetic behavior, the other two show sharp multiple magnetization steps across the antiferromagnetic-ferromagnetic transition region. Temperature and time dependences of magnetization show that the compounds with x Ն 0.025 possess glassy behavior at low temperatures. The experimental findings clearly establish the fact that among the intermetallics, the Ga-doped CeFe 2 shows the closest resemblance with the martensitic scenario seen in the phase-separated magnetic oxides.

Metastable magnetization behavior of magnetocaloric R6Co1.67Si3 (R=Tb and Nd) compounds

“…Nd 6 Co 1.67 Si 3 has T C =86 K and T * =39 K, in agreement with the values reported earlier [14]. It is noteworthy that though the impurity content was much less in this compound, the M-T behavior is almost identical to that of compound across the field induced antiferromagnetic to ferromagnetic phase transition [6,8,9]. However, unlike doped CeFe 2 , in the present case, there is a large remanence at low temperatures.…”

“…It is to be noted that the step size and the location are the same in both the modes except in the 1 st loop. The step behavior and the hysteresis have been attributed to the characteristic features of the first order phase transition [8]. As mentioned earlier, usually the first order transitions…”

“…Therefore, to find the relaxation time scales, magnetization data was recorded in the interrupted sweep mode as was reported earlier in Ga doped CeFe 2 compound and in manganites [8,17,18]. In this mode, the field was held constant for 80 minutes at indicates that the material undergoes a field induced magnetic transition through highly metastable states and that the field-induced transition is of first order type.…”

“…Realization of step behavior in the magnetization [2] and the possibility to use as room temperature magnetic refrigerant materials [3] have made this series important from the point of view of both fundamental interest as well as applications. Unusual magnetization steps and time relaxation of magnetization across the metamagnetic transition have been observed in a few intermetallics and oxides [4][5][6][7][8][9].…”

Magnetostructural transition in Ce(Fe0.975Ga0.025)2 compound

“…Recently, we have reported the magnetic properties of Ce(Fe 1-x Ga x ) 2 [15]. It was shown that in Ce(Fe 1-x Ga x ) 2 , the low temperature antiferromagnetic (AFM) state can be stabilized only for x≥0.025.…”