Magnetization and Curie Temperature of Ilmenite–Hematite Ceramics

Navarrete, L.; Dou, Henri; Allen, D. M.; Schad, R.; Padmini, P.; Kale, P.; Pandey, R. K.

doi:10.1111/j.1551-2916.2006.00953.x

Cited by 24 publications

(18 citation statements)

References 16 publications

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“…Figure 1 shows the X-ray diffraction pattern for the 0.9FeTiO 3 -0.1Fe 2 O 3 solid solution. All peaks correspond to the FeTiO 3 -Fe 2 O 3 solid solution system of rhombohedral structure [5]. The sample did not show any secondary phases.…”

Section: Methodsmentioning

confidence: 97%

“…All Fe 3+ moments are parallel within a given c-plane and antiparallel between adjacent planes, forming magnetic sublattices A and B [3]. Extensive investigation of the FeTiO 3 -Fe 2 O 3 system has previously been carried out with the magnetic and neutron diffraction measurements in the past [1,[3][4][5][6]. We have paid particular attention to the unusual magnetic properties on the ilmenite side of the composition range.…”

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confidence: 98%

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Mössbauer studies of Fe2 + and Fe3 + mixed state in ilmenite–hematite solid solution

2008

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The 0.9FeTiO 3 -0.1Fe 2 O 3 solid solution was prepared by solid state reaction with FeTiO 3 and α-Fe 2 O 3 powders, and studied by x-ray diffraction, Mössbauer spectroscopy, and vibrating sample magnetometer (VSM). The crystalline structure was found to be single phase rhombohedral structure with lattice constant a = 5.089 Å and c = 14.051 Å. Mössbauer spectra of 0.9FeTiO 3 -0.1Fe 2 O 3 solid solution were taken at various temperatures ranging from 4.5 to 300 K. The anomalous absorption curves at low temperature are observed. Mössbauer spectra at 4.5 K was fitted to four six-line hyperfine pattern with magnetic hyperfine fields H hf = 504, 424, 115, and 58 kOe, respectively. At 40 K the spectrum shows the mixture of ferromagnetic six-line pattern and paramagnetic two-line and above 50 K it show asymmetry two-line patterns. The fitted curves at room temperature are obtained by superimposing two doublets corresponding to Fe 2+ and Fe 3+ . The isomer shift δ and quadrupole splitting ΔE Q of sample are 0.92 and 0.69 mm/s for Fe 2+ and 0.14 and −0.29 mm/s for Fe 3+ , respectively. Corresponding relative absorption subspectral areas are 89.2% for Fe 2+ and 10.8% for Fe 3+ . Magnetization measurements indicate ferromagnetic behaviour with 92 Oe coercivity value at 50 K but at 300 K it show no hysteresis loop.

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Section: Methodsmentioning

confidence: 97%

mentioning

confidence: 98%

Mössbauer studies of Fe2 + and Fe3 + mixed state in ilmenite–hematite solid solution

2008

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“…It is to be noted that many of its members have magnetic Curie points well above room temperature [1,2,5,[8][9][10][11] in contrast to actively studied spintronics materials belonging to dilute magnetic systems, for example, Mn-doped GaAs and doped ZnO with the magnetic Curie points below room temperature. Furthermore, the nature of the magnetism in IH system is intrinsic and samples can be processed so that magnetism is uniformly distributed over the bulk of the sample and does not exist simply in clusters [5,11,12].…”

Section: Introductionmentioning

confidence: 93%

“…Bulk ceramic samples were prepared using the standard technique of ball milling the raw materials, pressing at high pressure using a uniaxial press followed by sintering and finally annealing the green ceramic at high temperatures. The details are given in many of our papers referenced here but the reference number [5,13,15] will be of special interest to those interested in processing dense, homogeneous ceramic samples of IH. We have studied also the textured and epitaxial films of different compositions of IH, primary among them being those with x=0.33 and x= 0.45.…”

Section: Sample Processingmentioning

confidence: 99%

Novel magnetic-semiconductors in modified iron titanates for radhard electronics

et al. 2008

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Some members of the modified iron titanate family show remarkable tolerance to radiation and are well suited for radhard electronics. Of particular interest are solid solutions of ilmenite-hematite (IH) represented by (1−x) FeTiO 3 .xFe 2 O 3 where x varies from 0 to 1; and pseudobrookite, Fe 2 TiO 5 (PsB). These multifunctional oxides can be both ferrimagnetic and wide bandgap semiconductors, and can be exploited in a variety of ways in radhard electronics, microelectronics and spintronics technologies. In this paper we emphasize the potential applications of the modified Fe-titanates with special emphasis on: (a) response of the non-linear current-voltage (I-V) characteristics to a magnetic field; (b) how the introduction of a biasing voltage might be used to produce bipolar currents in circuits and fabrication of voltage tunable varistors; and (c) the response of non-linear current-voltage characteristics when irradiated with neutrons, protons and heavy Fe-ions. Based on these observations, we will identify a few applications for which we can make use of the unique multifunctional nature of modified Fe-titanates.

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“…6 Its magneto-resistive characteristics and temperature dependent magnetization are covered in reference . 6,7 A well-defined saturated magnetic hysteresis loop is displayed at room temperature with saturation happening around H ≈ 4000 Oe. 6 Both IHC33 and IHC45 are also excellent radhard materials.…”

confidence: 99%

Magnetically tuned varistor-transistor hybrid device

et al. 2012

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The paper deals with the effect of magnetic fields on the I-V characteristics of an IHC45 varistor. It is found that: (a) the nonlinear I-V characteristics of the varistor can be tuned by a magnetic field resulting in enhanced device performance; and (b) the contributions of a magnetic field on the output signal show all the characteristics of a typical transistor. The potential applications of these devices could be magnetically controlled voltage amplifiers, magnetically controlled current amplifiers, sensors, memory elements, microphone pickup with integrated pre-amplifier using a single transistor, and high temperature electronics

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Magnetization and Curie Temperature of Ilmenite–Hematite Ceramics

Cited by 24 publications

References 16 publications

Mössbauer studies of Fe2 + and Fe3 + mixed state in ilmenite–hematite solid solution

Mössbauer studies of Fe2 + and Fe3 + mixed state in ilmenite–hematite solid solution

Novel magnetic-semiconductors in modified iron titanates for radhard electronics

Magnetically tuned varistor-transistor hybrid device

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