Spontaneous magnetization and resistivity steps in the bilayered manganite(La0.5Nd0.5)1.2Sr1.8Mn2

Abstract

We report a detailed study of steplike magnetization and resistivity jumps in a bilayered ͑La 0.5 Nd 0.5 ͒ 1.2 Sr 1.8 Mn 2 O 7 single crystal. The sample exhibits very sharp metamagnetic transitions at low temperature when the magnetic field is applied either in an ab plane or along the c axis, which causes huge magnetization steps. The critical field depends on the cooling magnetic field as well as the sweep rate of the magnetic field. Meanwhile, the evolution with time of the magnetization exhibits a spontaneous step when both the temperature and magnetic field are constant. Similar steplike behaviors are also observed in resistivity. These results suggest that a martensiticlike transformation could happen in bilayered manganites.

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

“…Therefore, the differences in the data observed in different magnetometers indicate the protocol dependence of magnetization in this system. Such dependence is a characteristic property of systems with slow kinetics, like the martensitic systems [11,19]. Temperature dependence of electrical resistivity has been studied in zero field and in a field of 5 kOe (Fig.…”

“…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].…”

Magnetism in gallium-dopedCeFe2: Martensitic scenario

“…The sweep rate dependence of the step behavior is a signature of martensitic strains in the system. 11,26 The effect of sweep rate was also investigated in another manner as shown in Fig. 8, which compares the M-H curves obtained in the normal sweep and in the interrupted sweep.…”

“…It has been reported that many manganites show multiple steps with reduction in temperature. [14][15][16][17][26][27][28] The M-H curves were also recorded without thermal cycling. Figure 5 shows the two loop magnetization isotherms for Ce͑Fe 0.975 Ga 0.025 ͒ 2 without thermal cycling.…”

“…The appearance of sharper steps under a fast sweep rate, compared to that with a slow sweep rate, is a characteristic of martensitic systems. 11,26 A slower sweep is supposed to transform the two phases smoothly, compared to the higher sweep rate. A gradual accommodation of martensitic strains during the field-induced order-order transition leads to higher critical field and fewer steps.…”