Effect of grain connectivity and density on the magnetoresistance in Ca or Li doped lanthanum manganites

Extrinsic inhomogeneity effects in magnetic, transport and magnetoresistive properties of () crystal prepared by the floating-zone method

“…Double-peaked (or shouldered) ρ(T ) curves similar to that shown in Fig. 4 were often seen in polycrystalline manganite samples [30,35,36,37,38]. In all cases this behavior was quite reasonably attributed to the influence of grain boundaries.…”

Structural, magnetic, magneto-transport properties and Bean–Rodbell model simulation of disorder effects in Cr3+ substituted La0.67Ba0.33MnO3 nanocrystalline synthesized by modified Pechini method

“…33 Mn 1Àx Cr x O 3 denoted as LBMCr x (x ¼ 0 (LBMO), 0.05, 0.08, 0.1, 0.12, 0.15 and 0.17) were prepared by the Pechini sol-gel method 20 using highly pure metal nitrates as starting materials (>99.99% purity): La(NO 3 ) 3 $6H 2 O, Ba(NO 3 ) 2 , Mn(NO 3 ) 2 $4H 2 O and Cr(NO 3 ) 3 $9H 2 O. The initial solution was prepared by mixing distilled water and the nitrates (properly weighed according to the specic composition), citric acid (CA) (99.5% purity) and ethylene glycol (EG) (99.5% purity) in the following molar proportion 1 : 5 : 4 : 3.…”

“…18,19 The rst aim of this study was to experimentally investigate the structural, magnetic and magneto-transport properties related to the substitution effect of Mn by Cr ions, up to 17%, in La 0.67 -Ba 0. 33 Mn 1Àx Cr x O 3 series, which has been prepared by the solgel method at low temperatures, resulting in small grain sizes. The second is to study on the effects of chromium inducing disorder effects of second-order phase transition of the system.…”

Magnetoresistance plateau in La2/3Ca1/3Bi x Mn1 − x O3 granular system

“…But It seems unreasonable that further increasing of x causes the increase of T m (as shown in Fig.2(b)) [5][6][7][8][9][10][11] . According to earlier research [16] , T m is also related to the connectivity between the grains, therefore this abnormality of T m should be attributed to the better connectivity between the grains in the x>0.05 samples. Fig.4 shows the temperature dependence of MR for all samples under an applied magnetic field of 3 000 Gs.…”