Magnetotransport properties of inverse-spinel CrxFe3−xO4 thin films

Kim, Kwang Joo; Lee, Hee Jung; Lee, Jung Han; Lee, Seungho; Kim, Chul Sung

doi:10.1063/1.3000625

Cited by 14 publications

(3 citation statements)

References 21 publications

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“…It is seen that M s , M r and H c exhibit decreasing trends with increasing x. If the spin of the substituting Cr 3+ ion aligns with the Fe 3+ ion, the spin magnetic moment (SMM) of Cr 3+ (d 3 ) ion is 3µ B ; thus, the net SMM is expected to be reduced by 2µ B per formula unit [14].…”

Section: Magnetic Propertiesmentioning

confidence: 99%

Dielectric relaxation and magnetic properties of Cr doped GaFeO₃

Mohamed¹,

Wang²,

Fueß³

2010

J. Phys. D: Appl. Phys.

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Polycrystalline GaFe 1-x Cr x O 3 (x= 0.05, 0.1 and 0.15) samples were prepared by solid state reaction. The monophasic compounds crystallize in the orthorhombic space group P c 2 1 n and the unit cell volume decreases with increasing Cr content. The saturated magnetization and magnetic transition temperature of the ceramics decrease due to the dilution of the magnetic interaction with Cr concentration. The dielectric properties were investigated from 133 to 353 K at various frequencies (100-10 7 Hz). Whereas the dielectric constant decreases with Cr-content an increase of dielectric loss tangent was observed. The activation energy of the compounds (calculated both from loss and modulus spectrum) are the same and have values~0.22 and 0.27 eV for Cr=10 and 15%, respectively, and hence the relaxation process may be attributed to the same type of charge carrier. A separation of the grain and grain boundary properties has been achieved using an equivalent circuit model. The capacitance and resistances associated with the grain boundary were found to be higher than that associated with grain. IntroductionThe study of multiferroics is a very hot topic. It is interesting not only from the point of view of fundamental physics but also for many potential applications in electronics [1,2].GaFeO 3 has an orthorhombic crystal structure (space group P c 2 1 n) with four different cation sites labeled Ga1, Ga2 (mostly occupied by gallium) and Fe1, Fe2 (mostly occupied by iron). This material has a spontaneous polarization along the b axis and a ferrimagnetic structure below room temperature result from unequal distribution of Fe spins of nearly equal magnitude on the sublattices with a magnetic moment of the spin along the c axis [3,4].GaFeO 3 contains only trivalent metals in the structure like rare earth orthoferrites, making them attractive systems for investigations of isovalent substitutions. In particular, the replacement of Fe 3+ by Cr 3+ and its effect on structural, magnetic and other properties have been reported [5][6][7] for rare earth orthoferrites. For example, in the lanthanum orthoferrites, partial replacement of Fe by Cr leads to a reduction in the Néel temperature from 750 K in LaFeO 3 to 280 K in LaCrO 3 . Moreover, Cr doping is one of the most adopted strategies to tailor the dielectric and piezoelectric properties of ferroelectrics for practical applications. It is well known that Cr is effective in decreasing the aging effect and the dielectric loss; thus, the effect of doping of Cr 3+ is that of a stabilizer of the piezoelectric and dielectric properties [8,9].In the present work we study the (a) magnetic properties, (b) apply the variablefrequency technique of impedance spectroscopy to the samples over a wide temperature range, and (c) characterize the grain and grain boundary resistance using IS, from which one can calculate their capacitance and can model the equivalent circuit for Cr-substituted GaFeO 3 samples.

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Section: Magnetic Propertiesmentioning

confidence: 99%

Dielectric relaxation and magnetic properties of Cr doped GaFeO₃

Mohamed¹,

Wang²,

Fueß³

2010

J. Phys. D: Appl. Phys.

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“…For [13][14][15][16][17][18][19][20][21]. Due to the fact that the spin directions of the 3d electrons in the cations are constrained by Hund's rules, we proposed a magnetic ordering model in ferrites (MOIF model) [22][23][24][25], in which the magnetic moment directions of the Cr 2 þ (3d 4 ) and Cr 3 þ (3d 3 ) cations for which the number of 3d electrons is n d r4, are assumed to be antiparallel to those of Fe, Co, Ni and Cu cations whether at the (A) sites or at the [B] sites of the spinel ferrites.…”

mentioning

confidence: 98%

Evidence from infrared spectra for the magnetic moment directions of CR cations in the spinel ferrites

Tang

Shang

Zhang

et al. 2015

Physica B: Condensed Matter

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“…3) [11]. Two-terminal memristive devices can be based on metal/oxide switches, such as for SiO x [12], HfO 2 [13], CuO [14], NiO [15], ZnO [16], Al 2 O 3 [17], VO 2 [18], SrTiO 3 [19]. These devices behave as solid-state electrochemical switches, whose resistance is defined by a metallic filament formation mechanism related to the solidstate redox reactions stimulated by the polarity of the applied electric field [20].…”

Section: Resistive Ramsmentioning

confidence: 99%