Ultrasharp Magnetization Steps in Perovskite Manganites

Abstract

We report a detailed study of steplike metamagnetic transitions in polycrystalline Pr0.5Ca0.5Mn0.95Co0.05O3. The steps have a sudden onset below a critical temperature, are extremely sharp (width <2x10(-4) T), and occur at critical fields which are linearly dependent on the absolute value of the cooling field in which the sample is prepared. Similar transitions are also observed at low temperature in non-Co doped manganites, including single crystal samples. These data show that the steps are an intrinsic property, qualitatively different from either previously observed higher temperature metamagnetic transitions in the manganites or metamagnetic transitions observed in other materials.

Magnetism in gallium-dopedCeFe2: Martensitic scenario

“…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.…”

“…11 Interestingly, single-step and multistep magnetization behaviors are observed in some mixed-valent manganites showing colossal magnetoresistance ͑CMR͒, even in polycrystalline form. [12][13][14][15][16][17][18][19][20] Basically, these materials are phaseseparated systems, and the transformation between the two phases has a martensitic character. In addition to the AFM-FM transition, it has been found that the breakdown of charge and orbital ordering also leads to the magnetization jumps in the case of manganites, in general.…”

Avalanche-like metamagnetic transition in (LaNd)CaMnO manganites

“…In manganites both phases coexist in low magnetic fields, and the broad metamagnetic transitions observed, are the result of an increasing field dependent fraction of the ferromagnetic phase within the phase-separated material. But in addition, measurements at very low temperatures (< 4 K) have revealed a surprising and beautiful effect: the observation of a discontinuous metamagnetic transition at a critical magnetic field [9,10,11]. This phenomenon, referred to as ultrasharp magnetization jumps, avalanche-like or abrupt metamagnetic transition, has puzzled the scientific community since it was first reported [12].…”

Magnetic avalanchelike behavior in the disordered manganite(Eu0.4La0.1)(Sr0.4Ca0.1)MnO3Rana1, Malik2 2006Phys. Rev. B221160View full textAdd to dashboardCite

“…This was first observed by Hebert et al 7 when the Mn sub-lattice was diluted with some magnetic or non-magnetic impurities and subsequently by Fisher et al 8 by augmenting the cation-disorder at the Asite 11 . Such low temperature metamagnetic behavior in manganite compounds is remarkable as these first order transitions display a crossover from a smooth to a sharp metamagnetic transition [7][8][9][10][11][12][13] .…”