Realizing the ‘hindered charge ordered phase’ in nanoscale charge ordered manganites: magnetization, magneto-transport and EPR investigations

Rao, S. Narasimha; Bhat, S. V.

doi:10.1088/0953-8984/21/19/196005

Cited by 28 publications

(18 citation statements)

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“…It signals field induced transition from the residual AFI-CO to the FMM state. 12 The reverse cycle (170 kOe→0) trace does not overlap with the warm up curve indicating a substantial magnetic hysteresis, 12 the effect being more pronounced at lower T. The observed M-H loop area gradually closes as the sample is warmed up to 70 K. Similar features were earlier reported 12 by conventional DC SQUID measurements performed on PCMO20, PCMO40, on Nd 0.5 Ca 0.5 MnO 3 nanoparticles 19 as well as on Al doped bulk PCMO. 20 Also, much sharper stair-case like metamagnetic transitions were seen in several other Pr and Nd based bulk manganites.…”

Section: B Pulse Field Magnetic Propertiessupporting

confidence: 83%

Martensite-like transition and spin-glass behavior in nanocrystalline Pr0.5Ca0.5MnO3

et al. 2011

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We report on isothermal pulsed (20 ms) field magnetization, temperature dependent AC – susceptibility, and the static low magnetic field measurements carried out on 10 nm sized Pr0.5Ca0.5MnO3 nanoparticles (PCMO10). The saturation field for the magnetization of PCMO10 (∼ 250 kOe) is found to be reduced in comparison with that of bulk PCMO (∼300 kOe). With increasing temperature, the critical magnetic field required to ‘melt’ the residual charge-ordered phase decays exponentially while the field transition range broadens, which is indicative of a Martensite-like transition. The AC - susceptibility data indicate the presence of a frequency-dependent freezing temperature, satisfying the conventional Vogel-Fulcher and power laws, pointing to the existence of a spin-glass-like disordered magnetic phase. The present results lead to a better understanding of manganite physics and might prove helpful for practical applications

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Section: B Pulse Field Magnetic Propertiessupporting

confidence: 83%

Martensite-like transition and spin-glass behavior in nanocrystalline Pr0.5Ca0.5MnO3

et al. 2011

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“…Recently, the studies on nanosized near half-doped manganites have received significant interest due to the observation of some exotic phenomena associated with size effects. − Rao et al reported that, in nanowires of Pr 0.5 Ca 0.5 MnO 3 , the charge ordering is weakened . Zhang et al demonstrated that, in La 0.25 Ca 0.75 MnO 3 , the CO temperature ( T CO ) decreases with the decrease of the particle size and that, in Pr 0.5 Ca 0.5 MnO 3 , the CO state is completely suppressed when the particle size is smaller than 40 nm .…”

Section: Introductionmentioning

confidence: 99%

Particle Size Effects on Charge and Spin Correlations in Nd_0.5Ca_0.5MnO₃ Nanoparticles

et al. 2011

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The particle size effects on the charge and spin correlations in half-doped manganite Nd0.5Ca0.5MnO3, which exhibits a charge-ordered (CO) transition at 250 K in the bulk counterpart, have been investigated by magnetometry and electron spin resonance (ESR). Magnetic measurements show that reducing the particle size weakens the long-range CO transition, which completely disappears when the particle size is reduced down to 40 nm. Meanwhile, a weak ferromagnetic (FM) behavior appears at low temperatures and is gradually enhanced with the decrease of the particle size. The ESR intensities of the nanoparticles reproduce well these features. However, the temperature dependences of the ESR g-factor and line width exhibit the typical characteristics of the CO states in all the nanoparticles, even in the 40 nm sample, which suggests that, even though the long-range CO transition is completely suppressed by the size reduction, the CO state is still present in the short-range ordering form. Moreover, it is found that the onset temperatures of the CO states in all the nanoparticles are almost the same as that of the bulk, which strongly indicates that the strength of the CO correlations in this compound is not influenced much by the particle size. A detailed analysis on the magnetic susceptibilities and the ESR line width further reveals that both the antiferromagnetic (AFM) and the FM spin interactions are weakened by the size reduction, which suggests that the enhanced FM behavior in the nanoparticles is not due to the enhancement of the double-exchange FM interactions. We propose that, although the FM interactions are weakened, they gradually dominate over the AFM ones at low temperatures with the decrease of the particle size due to the more significant weakening of the latter by the size reduction, which, hence, gives rise to the development of the FM behaviors in the nanoparticles.

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“…The phenomena, that is the particle size dependent enhancement of MR also appears to be playing role in several other manganite compounds. The indication of reduction of the required external magnetic field value (H C ) in nano particles of Pr 0.5 Ca 0.5 MnO 3 (particle size ~40 nm and H C = 55 kOe) compared to their respective bulk counterpart (H C = 270 kOe) was reported in earlier studies1314.…”

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confidence: 56%

Significant enhancement of magnetoresistance with the reduction of particle size in nanometer scale

Das

Dasgupta

Poddar

et al. 2016

Sci Rep

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The Physics of materials with large magnetoresistance (MR), defined as the percentage change of electrical resistance with the application of external magnetic field, has been an active field of research for quite some times. In addition to the fundamental interest, large MR has widespread application that includes the field of magnetic field sensor technology. New materials with large MR is interesting. However it is more appealing to vast scientific community if a method describe to achieve many fold enhancement of MR of already known materials. Our study on several manganite samples In present days science based society largely depends on several gadgets where magnetic field sensors play crucial role. The primary requirement for magnetoresistive sensor is the large magnetoresistance. Last two decades perovskite manganites was in the fore-front of the experimental research and resulted several thousand research articles with the primary focus on large magnetoresistance (MR). However, in manganites most of the cases large magnetoresistance occurs at very high (several tesla or more) magnetic field. The requirement of the large external magnetic field severely restrict the use of manganites as magnetic field sensor. Our findings in this manuscript show how the MR of the same material can be increased drastically even at the lower magnetic field.The doped perovskite manganite is generally represented by the formula R 1−x B x MnO 3 , where 'R' is a trivalent rare earth and 'B' is a bivalent element. Numerous fascinating properties of the doped manganites were observed depending on the bivalent element B and its doping concentration x. In addition to the metal-insulator transition and colossal magnetoresistance, doped manganite compounds usually show a generic phenomenon of charge ordering close to the doping concentrations x ~ 1 2 , 3 8 and some other concentrations. The charge-ordering (CO) is the real space ordering of the Mn 3+ and Mn 4+ ions and it is generally followed by an antiferromagnetic transition with the lowering of temperature. The high resistive insulating behavior with lowering the temperature below the charge-ordering transition temperature is also a generic behavior of the charge-ordered manganites. In the presence of external perturbations like magnetic field, electric field, x-ray irradiation etc., the high resistive insulating state transforms into a low resistive metallic state as a results of destabilization of the charge ordering. The magnetic field-induced destabilization of the charge ordering leads to the gigantic change of the resistance which is known as colossal magnetoresistance. The required magnetic field to destabilize the charge ordered state depends upon the electronic band width of the compounds and the charge-ordered state is more robust for lower band width system. During the last two decades, magnetoresistive properties of several doped perovskite manganites were extensively studied 1-8 . To consider manganites for technological purposes such as magnetic field sensor, the hi...

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Realizing the ‘hindered charge ordered phase’ in nanoscale charge ordered manganites: magnetization, magneto-transport and EPR investigations

Cited by 28 publications

References 50 publications

Martensite-like transition and spin-glass behavior in nanocrystalline Pr0.5Ca0.5MnO3

Martensite-like transition and spin-glass behavior in nanocrystalline Pr0.5Ca0.5MnO3

Particle Size Effects on Charge and Spin Correlations in Nd_0.5Ca_0.5MnO₃ Nanoparticles

Significant enhancement of magnetoresistance with the reduction of particle size in nanometer scale

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Realizing the ‘hindered charge ordered phase’ in nanoscale charge ordered manganites: magnetization, magneto-transport and EPR investigations

Cited by 28 publications

References 50 publications

Martensite-like transition and spin-glass behavior in nanocrystalline Pr0.5Ca0.5MnO3

Martensite-like transition and spin-glass behavior in nanocrystalline Pr0.5Ca0.5MnO3

Particle Size Effects on Charge and Spin Correlations in Nd0.5Ca0.5MnO3 Nanoparticles

Significant enhancement of magnetoresistance with the reduction of particle size in nanometer scale

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Particle Size Effects on Charge and Spin Correlations in Nd_0.5Ca_0.5MnO₃ Nanoparticles